While AORC occurs in children, it is difficult to acquire population data on them, so most of the estimates presented in this report are for adults unless otherwise noted.

 In the general population, prevalence is better estimated by DDA than AORC. For the years 2013-2015, DDA affected an unadjusted average of 54.4 million adults, or 23 in 100 adults.1 Estimates show the typical distribution of higher prevalence among females and older adults, and lower prevalence among Hispanics and Asians. Absolute estimates show that most of these adults (59%, or 32.2 million) are of working age (younger than age 65).1 (Reference Table 3A.1.1 PDF [7] CSV [8])

 

Specific types of AORC  

Clinical data are required to provide some measure of validity for estimating the prevalence of specific types of arthritis because many people are not sure what type of arthritis they have. Data from the National Arthritis Data Workgroup provided 2005 national prevalence estimates for some of the ten specific types of arthritis used in later tables.2^,3 Respondents could have reported more than one type.

Osteoarthritis:  Osteoarthritis (OA) is the most common type of arthritis, characterized by progressive damage to cartilage and other joint tissues. Joint injury is a risk factor for OA, but most cases occur without a specific history of injury. Obesity is a risk factor for knee OA, and to a lesser extent for hip and hand OA. Clinical OA was estimated to affect 26.9 million in 20053 and over 30 million for 2008-2011.4 The joints most affected with radiographic OA and symptomatic OA were hands, knees, and hips.3  

Rheumatoid arthritis:  Rheumatoid arthritis (RA) is the prototypical inflammatory arthritis. It is a chronic autoimmune disease that causes pain, aching, stiffness, and swelling in multiple joints, especially the hands, in a symmetrical fashion. In 2005, RA was estimated to affect 1.3 million adults.2
 
Gout and other crystal arthropathies:  Gout is a recurrent inflammatory arthritis that occurs when excess uric acid collects in the body. Gout has been recognized for centuries and often affects the big toe. In 2005, an estimated 6.1 million adults reported having gout at some time, with 3.0 million affected in the past year.3 More recent studies of self-reported gout and hospitalizations show the prevalence of gout increasing in the last two decades.5^,6

Joint pain/effusion/other unspecified joint disorders: Joint pain can result from several causes, including inflammation, degeneration, crystal deposition, infection, and trauma. Joint pain is often accompanied by swelling and effusion. A joint effusion is the presence of increased intra-articular fluid within the synovial compartment of a joint. Determining the cause of joint pain is primary to treatment.

Spondylarthropathies:  Spondylarthropathies (or spondylarthritides) are a family of diseases that includes ankylosing spondylitis, reactive arthritis, psoriatic arthritis, enteropathic arthritis (associated with ulcerative colitis or Crohn’s disease), juvenile spondylarthritis, and undifferentiated spondylarthritis. In 2005, spondylarthropathies affected an estimated 639,000 to 2.4 million adults ages 25 and older.2

Fibromyalgia:  Fibromyalgia (FM) is a syndrome of widespread pain and tenderness. The diagnosis is difficult to make, so relevant prevalence data are hard to come by. In 2005, FM was estimated to affect around 5 million adults.3 A more recent estimate by the National Fibromyalgia Association puts the estimate at 10 million people in the US, with 75%-90% of the affected adult women. However, due to the difficulty in diagnosing fibromyalgia and the potential for including other causes of pain, this estimate should be used with caution.7  

Diffuse connective tissue diseases include the next four diseases.
Systemic lupus erythematosus:  Systemic lupus erythematosus (SLE) is the prototypical autoimmune disease in which the body’s immune system can attack many body systems, especially the skin, kidneys, and joints. In 2005, definite and suspected SLE was conservatively estimated to affect 322,000.2 Population-based registries have provided more recent estimates for various racial/ethnic groups.8^,9^,10

Systemic Sclerosis:  Systemic sclerosis (SSc), or scleroderma, is an autoimmune disease that primarily affects the skin, but can affect any organ system. In 2005, SSc affected an estimated 49,000 adults.2

Primary Sjögren’s Syndrome:  Primary Sjögren’s Syndrome (SS) is a syndrome of dry eyes, dry mouth, and arthritis. Secondary SS can occur in association with other rheumatologic diseases such as rheumatoid arthritis and lupus. Prevalence data are very limited. In 2005, an estimated 0.4 to 3.1 million adults had SS.2

Polymyalgia rheumatica and giant cell (temporal) arteritis: Polymyalgia rheumatica (PMR) is a syndrome of sudden aching and stiffness in older adults that responds to treatment with anti-inflammatory medications (e.g., corticosteroids). Giant cell arteritis (GCA), which often occurs with PMR, is a type of vasculitis that affects medium-size arteries and results in headache, vision loss, and other symptoms. In 2005, PMR was estimated to affect 711,000 adults;3 a more recent analysis from the same data source found that the incidence of PMR had increased slightly with mortality not unlike the general population,11 suggesting that prevalence may have increased slightly as well. In 2005, GCA was estimated to affect 228,000 adults.4  

Carpal tunnel syndrome: Carpal tunnel syndrome (CTS) occurs when the median nerve becomes compressed at the wrist and causes numbness, pain, or weakness in part of the hand. Thickened tendons and other rheumatic conditions are a common cause. General population prevalence has been reported between 1% and 5%.12

Soft tissue disorders (excluding back): These are a variety of problems of the tendons, bursa, muscle, ligaments, and fascia that cause pain and dysfunction. Prevalence of soft tissue disorders is difficult to determine due to the variety of conditions included.

Other specific rheumatic conditions: These are other conditions that the National Arthritis Data Workgrop considered to be rheumatic conditions.

Juvenile arthritis:  Arthritis and other rheumatic conditions are relatively uncommon in children, although they can be particularly severe when they do occur. One estimate using significant pediatric arthritis and other rheumatologic conditions (SPARC) codes put the average annual prevalence at 103,000 children for the years 2001-2004 for the combined codes for rheumatoid arthritis and other inflammatory polyarthropathies, allergic purpura, arthropathy associated with infections, other and unspecified arthropathies, polyarteritis nodosa and allied conditions, and rarer inflammatory conditions.The prevalence for all SPARC codes, including synovitis and myalgia, was 294,000.13 A more in-depth discussion can be found in the Juvenile Arthritis (click HERE [11] to open new page) section later in this document.

• 1. a. b. Barbour KE, Helmick CG, Boring M, Brady TJ.  Prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation—United States, 2013-2015.  MMWR 2017;66(9):246-253.
• 2. a. b. c. d. e. f. Helmick CG, Felson DT, Lawrence RC, et al., for the National Arthritis Data Workgroup. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States:  Part I. Arthritis Rheum 2008;58(1):15-25.
• 3. a. b. c. d. e. f. Lawrence RC, Felson DT, Helmick CG, et al., for the National Arthritis Data Workgroup. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States:  Part II. Arthritis Rheum 2008;58(1):26-35.
• 4. a. b. Cisternas MG, Murphy L, Sacks J, et al.,  Alternative methods for defining osteoarthritis and the impact on estimating prevalence in a US population-based survey. Arthritis Care Res 2016;68(5):574-580.
• 5. Lim SY, Lu N, Oza A, et al., Trends in gout and rheumatoid arthritis hospitalizations in the United States, 1993-2011. JAMA. 2016:315(21);2345-2346.
• 6. Roddy E, Choi H. Epidemiology of gout. Rheum Dis Clin North Am. 2014:40(2);155-175. Doi: 10.1016/j.rdc.2014.01.001.
• 7. National Fibromyalgia Association.  http://www.fmaware.org/about-fibromyalgia/prevalence [12]/ Accessed April 18, 2017.
• 8. Lim SS, Bayakly AR, Helmick CG, et al., The incidence and prevalence of systemic lupus erythematosus, 2002-2004: The Georgia Lupus Registry. Arthritis Rheum 2014;66(2):357-368.  DOI 10.1002/art.38329.
• 9. Somers EC, Marder W, Cagnoli P, et al., Population-based incidence and prevalence of systemic lupus erythematosus: The Michigan Lupus Epidemiology & Surveillance Program. Arthritis Rheum 2014;66(2):369-378.  DOI 10.1002/art.38328.
• 10. Ferucci ED, Johnston JM, Gaddy JR, et al., Prevalence and incidence of systemic lupus erythematosus in a population-based registry of American Indian and Alaska Native people, 2007-2009. Arthritis Rheum 2014;66(9):2494-2502. DOI 10.1002/art.38720.
• 11. Raheel S, Shbeeb I, Crowson CS, Matteson EL.  Epidemiology of polymyalgia rheumatica 2000-2014 and examination of incidence and survival trends over 45 years: A population-based study.  Arthritis Care Res (Hoboken). 2016 Oct 21. doi: 10.1002/acr.23132. [Epub ahead of print] PMID: 27768840.
• 12. Dale AM, Harris-Adamson C, Rempel D. et al. Prevalence and incidence of carpal tunnel syndrome in US working populations: Pooled analysis of six prospective studies. Scand J Work Environ Health. 2013 Sep 1; 39(5): 495–505. doi:  10.5271/sjweh.3351.
• 13. Sacks JJ, Helmick CG, Luo Y-H, et al., Prevalence of and annual ambulatory healthcare visits for pediatric arthritis and other rheumatologic conditions in the US in 2001–2004. Arthritis Rheum (Arthritis Care Res) 2007;57(8):1439-1445.

AORC prevalence continues to increase in the aging US population, with related increases in healthcare utilization. The increase in total ambulatory care visits, together with the increasing number of joint replacements and related hospitalizations, both impact healthcare utilization. The AORC case definition is more appropriate to use within the healthcare system, which is based on health condition codes. However, the AORC case definition will miss adults with mild arthritis that is not mentioned at the visit, or for whom arthritis may not be a priority when multiple conditions are present. For estimates in the following discussions, AORC condition codes, found in ICD-9-CM Codes [13] section are used.

In 2013, AORC-related diagnoses were listed in 105.7 million healthcare visits and represented more than 10% of all healthcare visits. Hospitalizations accounted for 6% of AORC visits, while ambulatory care accounted for 94% (77% physician office, 6% outpatient, and 11% emergency department). (Reference Table 3A.3.0.1 PDF [14] CSV [15])

When looking at how the ten subtypes of AORC affect the four types of healthcare utilization below, remember that the estimates are not mutually exclusive due to the potential for multiple diagnoses in a single visit. (Reference Table 3A.3.0.2 PDF [18] CSV [19]; Table 3A3.0.3 PDF [20] CSV [21]; Table 3A.3.0.4 PDF [22] CSV [23]; and Table 3A.3.0.5 PDF [24] CSV [25])

Hospitalizations

The Healthcare Cost and Utility Project (HCUP) 2013 Nationwide Inpatient Sample (NIS) estimates that 6.4 million hospitalizations were associated with a diagnosis of AORC, or 21.4% of all hospitalizations that year. AORC was the presenting or first-listed diagnosis for only 1% of all hospitalizations, suggesting the role of AORC is more of an important comorbidity or contributor to other conditions which are the reason for the hospitalization. Nearly one-half of the 6.4 million AORC hospitalizations were associated with osteoarthritis (46%), while joint pain/effusion/other unspecified joint disorders, gout, and soft tissue disorders were each listed in more than 10% of hospitalizations. Multiple AORC diagnoses are coded in 17% of hospitalizations with an AORC diagnosis. Osteosteoarthritisrthritis is the least likely to have another AORC diagnosis, while carpal tunnel syndrome is most likely to include multiple diagnoses. (Reference Table 3A.3.0.1 PDF [14] CSV [15] and Table 3A.3.0.2 PDF [18] CSV [19])

AORC-associated hospitalizations by sex, race/ethnicity, and geographic region resembled those for all 2013 hospitalizations; however, they differed in age, skewing toward the 65 & older age group (59.1% vs. 41.7%). (Reference Table 3A.3.1.0.1 PDF [26] CSV [27]; Table 3A.3.1.0.2 PDF [28] CSV [29]; Table 3A.3.1.0.3 PDF [30] CSV [31]; Table 3A.3.1.0.4 PDF [32] CSV [33])  

Hospitalizations for specific types of AORC differed by demographic variables. Women comprised 59% of total AORC hospitalizations, but much more for hospitalizations with rheumatoid arthritis (75%), fibromyalgia (89%), and diffuse connective tissue disease (87%).  Men comprised 41% of total AORC hospitalizations, but much more for hospitalizations with gout (67%) and soft tissue disorders (52%). (Reference Table 3A.3.1.0.1 PDF [26] CSV [27])

Those younger than age 65 comprised 41% of total AORC hospitalizations, but much more for hospitalizations with fibromyalgia (68%), diffuse connective tissues disease (67%), and carpal tunnel syndrome (61%). (Reference Table 3A.3.1.0.2 PDF [28] CSV [29])

 Non-Hispanic blacks comprised 12% of total AORC hospitalizations, but much more for hospitalizations with gout (18%) and diffuse connective tissue disease (24%). (Reference Table 3A.3.1.0.3 PDF [30] CSV [31])  

Hospitalizations for specific types of AORC did not differ much by geographic region. (Reference Table 3A.3.1.0.4 PDF [32] CSV [33])

Length of Stay (LOS)

The mean LOS for AORC-associated hospitalizations in 2013 was slightly greater than that for all hospitalizations (4.9 vs 4.7 days); differences by demographic groups were greater for AORC hospitalizations (than all hospitalizations) for women (4.8 vs 4.4 days), those 18 to 44 years (5.0 vs. 3.6 days), non-Hispanic blacks (5.6 vs 4.4 days), Hispanics (5.3 vs. 3.6 days), and those in the western geographic region (4.8 vs. 4.3 days). Among the 10 specific types of AORC the mean LOS was strikingly longer for those with soft tissue disorders and other specified rheumatic conditions both overall (6.5 and 6.5 vs. 4.9 days) and by every demographic subgroup. (Reference Table 3A.3.1.1.1 PDF [38] CSV [39]; Table 3A.3.1.1.2 PDF [40] CSV [41]; Table 3A.3.1.1.3 PDF [42] CSV [43]; Table 3A.3.1.1.4 PDF [44] CSV [45]) 

 

Hospital Charges

Hospital charges are based on individual record discharges. The fees included may vary from patient to patient, but generally include hospital room, supplies, medications, laboratory fees, and care staff, such as nurses. They generally do not include professional fees (doctors) and non-covered charges. Emergency charges incurred prior to admission to the hospital may be included in total charges. It is important to note that charges are not necessarily the actual amount paid by Medicare, insurers, or patients. However, they are the only medical expenditure cost available in the major databases based on ICD-9-CM diagnostic codes and provide an overall picture for comparison purposes. Because multiple diagnoses are often made with an admission, actual charges related to a specific AORC may be much smaller. This is true of cost estimates provided in the Economic Burden [48] section also.

Mean hospital charges for AORC-associated hospitalizations generally paralleled, but were consistently higher than charges for all hospitalizations, both overall (+$5,900) and for all demographic subgroups. Higher mean charges among demographic subgroups were most striking for women (+$8,200), persons 18-44 years (+$18,800), non-Hispanic whites (+$9,900), non-Hispanic blacks (+$10,900), Hispanics (+$33,700), other non-Hispanics (+$10,700), and those in the South (+$9,500) and West (+$16,100).

Total charges for AORC-associated hospitalizations were $310.9 billion in 2013, comprising 24% of all hospital charges for the year. This percentage was relatively consistent for all sex and age groups except those 18 to 44 years, where it was only 11%. Among racial/ethnic groups, AORC total charges were 19% for non-Hispanic others, while they were 30% among non-Hispanic whites. AORC-associated hospitalization total charges were 29% of all hospitalizations in the Midwest in 2013.

Among the 10 AORC subgroups, hospitalizations with osteoarthritis accounted for $138.4 billion, or 45% of total charges for AORC-associated hospitalizations, while hospitalizations with joint pain/effusion/other, gout, and soft tissue disorders accounted for 16%, 13%, and 13% respectively). (Reference Table 3A.3.1.1.1 PDF [38] CSV [39]; Table 3A.3.1.1.2 PDF [40] CSV [41]; Table 3A.3.1.1.3 PDF [42] CSV [43]; Table 3A.3.1.1.4 PDF [44] CSV [45])

 

Discharge Status

Discharge from the hospital to long-term care, which includes skilled nursing facilities, intermediate care, and other similar facilities, or to home health care occurred more frequently among AORC-associated hospitalizations than among all hospitalizations (44% vs 29%). This was true regardless of sex, age, race/ethnicity, or region of residence. By demographic characteristics, the highest proportion of discharge to long-term care or home health care was found among females (48%), age 65 and over (55%), and residents of the Northeast region (52%).

Among the 10 AORC subgroups there were no striking differences in discharge to long-term care or home health care compared with all AORC hospitalizations. Discharge to home was more frequent, and resembled all hospitalizations (66%), among those with carpal tunnel syndrome (68%), fibromyalgia (67%), diffuse connective tissue disease (64%), and spondylarthropathies (59%). (Reference Table 3A.3.1.3.1 PDF [51] CSV [52]; Table 3A.3.1.3.2 PDF [53] CSV [54]; Table 3A.3.1.3.3 PDF [55] CSV [56];Table 3A.3.1.3.4 PDF [57] CSV [58])

 

Ambulatory Care Visits

From the 2013 surveys on ambulatory care, there were an estimated 99.3 million ambulatory care visits associated with a diagnosis of AORC, more than 10% of all ambulatory care visits that year, for a rate of 40.1/100 adults in the general population. An AORC-related condition was listed as the presenting (first) diagnosis for between 2.8% and 5.4% of all ambulatory care visits, depending on the healthcare site visited. Physicians’ offices accounted for 82% of all ambulatory AORC visits, vastly exceeding emergency department (12%) or outpatient (7%) sites. (see Table 3A.3.0.1 PDF [14] CSV [15]) As with hospital discharges, multiple AORC diagnoses were given in 15% to 20% of patient ambulatory visits. (Reference Table 3A.3.0.3 PDF [20] CSV [21]; Table 3A.3.0.4 PDF [22] CSV [23]; and Table 3A.3.0.5 PDF [24] CSV [25])

In 2013, AORC-associated ambulatory care visits resembled all 2013 ambulatory care visits by sex, race/ethnicity, and geographic region; they differed in age, being lower in the 18 to 44-year age group (21% vs. 32%) and higher in the 45 to 64-year age group (44% vs. 36%) and the 65 and older age group (34% vs. 32%).  (Reference Table 3A.3.2.0.1 PDF [61] CSV [62]; Reference Table 3A.3.2.0.2 PDF [63] CSV [64]; Table 3A.3.2.0.3 PDF [65] CSV [66]; Table 3A.3.2.0.4 PDF [67] CSV [68]) (Note: Detailed data by type of ambulatory setting shown in Tables 3A.3.2.1.x, 3A.3.2.2.x(.1 to .4), and 3A.3.2.3.x, and can be accessed from the “Tables” tab in the upper right corner.)

Among the 10 AORC subgroups, 2 in 5 of the 99.3 million total ambulatory visits (41%) were associated with joint pain/effusion/other unspecified joint disorders or “other specified rheumatic conditions”; osteosteoarthritisrthritis and soft tissue disorders were the most common specific condition (~20% each). (Reference Table 3A.3.2.0.1 PDF [61] CSV [62])

AORC-associated ambulatory care visits for specific types of AORC differed by demographic variables.  Women comprised 62% of all AORC-associated ambulatory care visits; their proportion was much higher for fibromyalgia (79%) and diffuse connective tissue disease (90%), but much lower for gout and other crystal arthropathies (27%). Men comprised 39% of all AORC-associated ambulatory care visits; their proportion was much higher for gout (72%). (Reference Table 3A3.2.0.1 PDF [61] CSV [62])

The 18 to 44-year old group comprised 21% of all AORC-associated ambulatory care visits; their proportion was a bit higher for diffuse connective tissue disease (31%), fibromyalgia (27%), and carpal tunnel syndrome (26%). Those aged 45 to 64 years comprised 44% of all AORC –associated ambulatory care visits; this proportion was similar for most specific types of AORC. Those aged 65 and older comprised 34% of all AORC-associated ambulatory care visits; their proportion was much higher for osteoarthritis (51%) and gout (50%), and much lower for fibromyalgia (20%). (Reference Table 3A.3.2.0.2 PDF [63] CSV [64])

Non-Hispanic whites (65% of the US population) comprised 73% of all AORC-associated ambulatory care visits, but only 59% of those for gout. Comparisons for other race/ethnic groups, as well as geographic regions were difficult to determine due to small sample sizes and unreliable data. (Reference Table 3A.3.2.0.3 PDF [20] CSV [21]; Table 3A.3.0.4 PDF [22] CSV [23])

 

Physician Office Visits

Some 81 million AORC-related ambulatory care visits were physician office visits (PHYS); these accounted for 82% of all ambulatory care visits.  An AORC-related condition was listed as the presenting (first) diagnosis for 5.4% of all PHYS visits. (Reference Table 3A.3.0.1 PDF [14] CSV [15])

Overall, 2013 AORC-related PHYS visits resembled those for all 2013 PHYS visits by sex, race/ethnicity, and geographic region; they differed in age, being lower in the 18 to 44-year age group (20% vs. 29%), higher in the 45 to 64-year age group (46% vs. 37%), and similar in the 65 and older age group (34%).

Among the 10 AORC subgroups, nearly 2 in 5 of the 81 million AORC-related PHYS visits (37%) were associated with joint pain/effusion/other unspecified joint disorders; osteoarthritis and soft tissue disorders were about 21% each. (Reference Table 3A.3.2.1.1 PDF [77] CSV [78])

AORC-related PHYS visits for specific types of AORC differed by demographic variables.  Women comprised 61% of all AORC-associated PHYS visits; their proportion was much higher for rheumatoid arthritis (77%) and diffuse connective tissue disease (90%).  Men comprised 39% of all AORC-associated PHYS visits; their proportion was much higher for gout (71%). (Reference Table 3A.3.2.1.1 PDF [77] CSV [78])

Persons aged 18 to 44 comprised 20% of all AORC-associated PHYS visits; their proportion was higher for diffuse connective tissue disease (29%) and soft tissue disorders (26%), while lower for osteoarthritis (7%) and rheumatoid arthritis (13%). Those aged 45 to 64 comprised 46% of all AORC–associated PHYS visits; their proportion pf PHYS visits was higher for fibromyalgia (55%) and carpal tunnel syndrome (50%).  Those aged 65 and older comprised 34% of all AORC-associated PHYS visits; their proportion was much higher for osteoarthritis (51%) (Reference Table 3A.3.2.1.2 PDF [79] CSV [80]).

Non-Hispanic whites comprised 74% of all AORC-associated PHYS visits; their proportion was higher for rheumatoid arthritis (80%), spondylarthropathies (79%), and lower for gout (65%) and carpal tunnel syndrome (68%). Comparisons for other race/ethnic groups were difficult to determine. (Reference Table 3A.3.2.1.3 PDF [81] CSV [82])  

There was little difference by geographic region. (Reference Table 3A.3.2.1.4 PDF [83] CSV [84]).

 

Outpatient Clinic Visits

Some 6.5 million AORC-related ambulatory care visits were to outpatient (OP) clinics; these accounted for 7% of all ambulatory care visits. An AORC-related condition was listed as the presenting (first) diagnosis for 4.4% of all OP visits. (Reference Table 3A.3.0.1 PDF CSV)2013 AORC-related OP visits resembled those for all 2013 OP visits by sex, race/ethnicity, and geographic region; they differed in age, being lower in the 18 to 44-year age group (25% vs. 38%), and higher in the 45 to 64-year age group (49% vs. 39%) and the 65 and older age group (27% vs. 23%) (Reference Table 3A.3.2.2.1 PDF [85] CSV [86]).

Among the 10 AORC subgroups, more than 2 in 3 of the 6.5 million AORC-related OP visits (69%) were associated with joint pain/effusion/other unspecified joint disorders and osteoarthritis; soft tissue disorders and rheumatoid arthritis accounted for about 12% each. (Reference Table 3A.3.2.2.2 PDF [87] CSV [88])

AORC-related OP visits for specific types of AORC differed by demographic variables. Women comprised 69% of all AORC-associated OP visits; their proportion was much higher for rheumatoid arthritis (83%) and diffuse connective tissue disease (88%). Men comprised 31% of all AORC-associated OP visits; their proportion was much higher for gout (81%) and osteoarthritis (67%) (Reference Table 3A.3.2.2.1 PDF [85] CSV [86]).

Persons aged 18 to 44 comprised 25% of all AORC-associated OP visits; their proportion was higher for diffuse connective tissue disease (38%) and carpal tunnel syndrome (38%). Those aged 45 to 64 comprised 49% of all AORC-associated OP visits; their proportion was higher for rheumatoid arthritis (63%). Those aged 65 and older comprised 27% of all AORC-associated OP visits; their proportion was much higher for osteoarthritis (40%) (Reference Table 3A.3.2.2.2 PDF [87] CSV [88]).

Non-Hispanic whites comprised 58% of all AORC-associated OP visits; their proportion was higher for spondylarthropathies (71%) and fibromyalgia (70%). Comparisons for other race/ethnic groups were difficult to determine. (Reference Table 3A.3.2.2.3 PDF [89] CSV [90])

There was little difference by geographic region. (Reference Table 3A.3.2.2.4 PDF [91] CSV [92])

 

Emergency Department Visits 

Emergency department (ED) visits for AORC-related diagnoses, totaling 11.7 million, accounted for 12% of all ambulatory care visits in 2013 and 11% of all emergency department visits. An AORC-related condition was listed as the presenting (first) diagnosis for 2.8% of all ED care visits. (Reference Table 3A.3.0.1 PDF [14] CSV [15])

2013 AORC-related ED visits resembled those for all 2013 ED visits by sex and geographic area; they differed in age, being lower in the 18 to 44-year age group (29% vs. 49%) and higher in the 45 to 64-year age group (34% vs. 29%) and the 65 and older age group (37% vs. 23%). (Reference Table 3A.3.2.3.2 PDF [93] CSV [94])

Among the 10 AORC subgroups, 3 in 5 of the 11.7 million AORC-related ED visits were associated with joint pain/effusion/other unspecified joint disorders and osteoarthritis; soft tissue disorders and fibromyalgia accounted for 13% and 12%, respectively. (Reference Table 3A.3.0.1 PDF [14] CSV [15])

AORC-related ED visits for specific types of AORC differed by demographic variables. Women comprised 61% of all AORC-associated ED visits; their proportion was much higher for rheumatoid arthritis (77%), fibromyalgia (79%) and diffuse connective tissue disease (90%). Men comprised 39% of all AORC-associated ED visits; their proportion was much higher for gout (69%). (Reference Table 3A.3.2.3.1 PDF [95] CSV [96])

Persons aged 18 to 44 comprised 29% of all AORC-associated ED visits; their proportion was higher for diffuse connective tissue disease (40%), fibromyalgia (43%), and carpal tunnel syndrome (51%). Those aged 45 to 64 comprised 34% of all AORC-associated ED visits; this proportion was similar for most specific types of AORC. Those aged  65 and older comprised 37% of all AORC-associated ED visits; their proportion was much higher for osteoarthritis (66%), rheumatoid arthritis (49%), gout (56%), spondylarthropathies (50%), and other specified rheumatic conditions (49%). (Reference Table 3A.3.2.3.2 PDF [93] CSV [94])

Race/ethnicity was not a defined variable in the NEDS database. There was little difference by geographic region. (Reference Table 3A.3.2.3.4 PDF [97] CSV [98])

Disease burden can be measured in many ways. This is particularly important for AORC, which has a modest effect on conveniently measured outcomes like mortality, but a much larger impact on less conveniently measured outcomes important to functionality for most people. Such outcomes include effects on work, health-related quality of life, independence, and ability to keep doing valued life activities. Three of these burdens, along with adverse life style factors that are associated with arthritis, are addressed in the estimates below.

Bed Days and Lost Work Days

Bed Days

Bed days are defined as spending one-half or more days in bed due to injury or illness, excluding hospitalization. Data are averaged over three years for the NHIS to achieve larger, more powerful sample sizes. For the years 2013-2015, the proportion who had bed days among adults with arthritis was higher than that for adults with any medical condition (45% vs. 41%). The 24.6 million adults with doctor-diagnosed arthritis and any bed days, 10% of the adult population, had an annual average of nearly 25 days spent in bed in the previous 12 months. This is far higher than the annual average of 14.5 bed days for the 41% of adults with bed days for any medical condition. Multiplying the 24.6 million adults by the mean bed days for arthritis resulted in 607 million bed days overall, or 55% of the 1.1 trillion bed days among adults reporting any medical condition. (Reference Table 3A.4.1.1 PDF [99] CSV [100])

Among adults with arthritis, females had a higher proportion than males of bed days (48% vs 41%) and a slightly higher mean number of days (25.6 vs. 23.1 days).  Females with arthritis accounted for 65% of total bed days in 2013-2015.  (Reference Table 3A.4.1.1 PDF [99] CSV [100])

Bed days are reported by a higher proportion of younger than by older adults with arthritis. Adults with arthritis had a higher proportion with bed days than adults reporting any medical condition in each age group: persons aged 18 to 44 years (59% vs. 46%), aged 45 to 64 years (50% vs. 41%), and aged 65 and older (35% vs. 31%).  This was also true for the average number of bed days: 18 to 44 years (20.1 vs 9.3 days), 45 to 64 years (26.4 vs. 17.3 days), and 65 and older years (24.7 vs. 22.0 days). (Reference Table 3A.4.1.2 PDF [101] CSV [102])

Among racial/ethnic groups, those with arthritis had similar proportions reporting bed days (range 43%-47%) and a similar average number of bed days (range 21.4-25.6). (Reference Table 3A.4.1.3 PDF [103] CSV [104])

In the different geographic regions, those with arthritis had similar proportions with bed days (range 43%-47%) and a similar average number of bed days (range 22.4-27.2). (Reference Table 3A.4.1.4 PDF [105] CSV [106])

 

Lost Work Days

Persons in the workforce are defined as adults having worked at a job in the past 12 months. In the 2013-2015 NHIS sample, 81% of those age 18 to 44 held a job (56% of workforce), 74% of persons aged 45 to 64 years held a job (38% of workforce), and 20% of persons aged 65 and older were still working, comprising just under 6% of the workforce. Among the persons aged 65 and older, 83% were age 74 and younger. By sex, 73% of males reported being in the workforce, while 62% of females worked in the past 12 months. Males represented 52% of the workforce.

Lost work days for persons in the workforce are defined as absence from work due to illness or injury in the past 12 months, excluding maternity or family leave. For the years 2013-2015, the proportion of persons who had lost work days among adults with arthritis was lower than that for adults with any medical condition (23% vs. 30%).  Among adults with doctor-diagnosed arthritis, 12.6 million in the workforce reported an average of 14.3 work days lost in the past 12 months, nearly 5 days more than the 9.4 work days reported by adults with any medical condition. This resulted in 180.9 million total lost work days among adults with arthritis who are in the workforce, or 34% of the 533.2 million work days lost among adults reporting any medical condition.

Among adults with arthritis, females and males in the workforce had similar proportions with lost work days (23%-24%) and similar mean number of lost work days (14.2-14.4).  Females accounted for 57% of total arthritis-attributed lost work days per year in 2013-2013 due to the higher number of females with arthritis. (Reference Table 3A.4.1.1 PDF [99] CSV [100])
 
Compared with older adults, younger adults with arthritis or any medical condition had a higher proportion of lost workdays.  Adults with arthritis had a higher proportion of lost work days than adults reporting any medical condition for persons aged 18 to 44 years (47% vs. 42%), but proportions were similar for the older age groups. Although, overall, the proportion of persons with DDA reporting lost work days was slightly less than was reported for any medical condition, the average number of lost work days was higher among adults with arthritis than adults with any medical condition: 18 to 44 years (13.4 vs 8.2 days), 45 to 64 years (14.6 vs. 10.8 days), and 65 and older (15.3 vs. 12.6 days).  Adults aged 45 to 64 accounted for 62% of total arthritis-related lost work days even though they only comprised 38% of the workforce and 47% of those with any medical cause. (Reference Table 3A.4.1.2 PDF [101] CSV [102])

Activity Limitations

Activity limitations are included in the National Health Interview Survey in both the family database and the adult database, with slightly different response codes. Respondents are asked first if they need help performing a variety of activities of daily living (ADL), such as personal care, bathing, eating, getting in/out of chair, and walking. They are also asked if they are “limited in the kind or amount of work” they can perform. If a limitation of any type has a “yes” response, respondents are shown a list of 34 possible medical conditions and asked to identify those that cause the limitation. Multiple causes may be identified. This section uses the adult database and focuses on cases where arthritis is identified as a cause of limitations. The variable AAAL, defined in the introduction to this arthritis section, is based on a single question in the NHIS1 and produces somewhat different numbers than this more inclusive definition of activity limitations.

Limitations in any activities of daily living (ADLs) include seven components.  Musculoskeletal-related ADLs include only the three limitations related to movement and action commonly associated with musculoskeletal diseases and are 1) “needing help with routine needs,” 2) ”needing help with personal care,” and 3) “having difficulty walking without equipment.” Other ADLs are related to memory, vision, hearing, and other limitations.

Of the 35.6 million adults with limitations in any ADL, 23% (8.0 million) named arthritis as a cause; the proportion jumped to 29% for those with a limitation in musculoskeletal-related ADLs. One-third (33%, 4.5 million of 13.9 million) of adults with difficulty walking identified arthritis as a cause. More than 1 in 4 attributed their need for help with routine needs (2.8 million) or personal care (1.5 million) to arthritis. (Reference Table 3A.4.2.1 PDF [111] CSV [112])
 
These numbers demonstrate the large impact of arthritis on adults with limitations in any ADL or in musculoskeletal related ADLs. The effect was much stronger among females than males (Reference Table 3A.4.2.1 PDF [111] CSV [112]) and among older adults. (Reference Table 3A.4.2.2 PDF [113] CSV [114])

Little difference was found between adults by race/ethnicity except for slightly higher proportion of non-Hispanic blacks attributing limitations to arthritis. (Reference Table 3A.4.2.3 PDF [115] CSV [116]). Geographic region in the US does not seem to be a factor. (Reference Table 3A.4.2.4 PDF [117] CSV [118])

Work limitations are defined here as those unable to work now due to health or limited in kind or amount of work (i.e., “unable to work” or “limited in work”). Of the 28.1 million adults with work limitations per year in 2013-2015, arthritis attributable work limitations (AAWL) affected on average 23% (6.4 million).  Among those with any medical condition limiting work, 23% attributed their inability to work now to arthritis, while 22% limited in kind or amount of work did so. Higher percentages of females and older workers identified arthritis as a cause for work limitations. There was little difference seen by race/ethnicity or geographical region. (Reference Table 3A.4.2.1 PDF [111] CSV [112]; Table 3A.4.2.2 PDF [113] CSV [114]; Table 3A.4.2.3 PDF [115] CSV [116]; and Table 3A.4.2.4 PDF [117] CSV [118]).

 

Quality of Life and Lifestyle Factors

Among persons with DDA, compared with those without DDA, Health-Related Quality of Life (HRQoL) is worse on several scales. When assessed by self-reported health status, 27% of those with DDA reported fair/poor health compared to 12% of those without DDA. The DDA group also reported a higher mean number of days in the past month with poor physical health (6.6 vs 2.5 days), poor mental health (5.4 vs 2.8 days), or days with limitations in usual activities (4.3 vs 1.4 days).2 Using the same “unhealthy days” measures, an analysis of 2014 Humana Medicare Advantage members found that those with arthritis had more total unhealthy days, by 2.2 days per year, than those without arthritis, and that comorbid arthritis associated with hypertension, diabetes, chronic obstructive pulmonary disease, and congestive heart failure resulted in significant increases in both physically and mentally unhealthy days.3
 
The prevalence of DDA and of AAAL is much higher among those with the adverse lifestyle factors of obesity, insufficient or no physical activity, and fair/poor self-rated health.4 (Reference Table 3A.4.3 PDF [123] CSV [124])

 

• 1. National Health Interview Survey 2013-2015. Question: “Are you limited in any way in any of your usual activities because of arthritis or joint symptoms?” https://www.cdc.gov/nchs/nhis/nhis_questionnaires.htm [125].
• 2. Furner SE, Hootman JM, Helmick CG, Bolen J, Zack MM. Health-related quality of life of US adults with arthritis: analysis of data from the Behavioral Risk Factor Surveillance System, 2003, 2005 and 2007. Arthritis Care Res 2011;63(6):788-799.
• 3. Havens MA, Slabaugh SL, Helmick CG, et al. Comorbid arthritis is associated with lower health-related quality of life in older adults with other chronic conditions, United States, 2013-2014. Prev Chronic Dis 2017;14:160495. DOI: https://doi.org/10.5888/pcd14.160495.  [126] https://www.cdc.gov/pcd/issues/2017/16_0495.htm  [127] Accessed September 8, 2017.
• 4. Barbour KE, Helmick CG, Boring M, Brady TJ. Vital signs: prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation — United States, 2013–2015. MMWR 2017;66:246–253. DOI: http://dx.doi.org/10.15585/mmwr.mm6609e1 [128].

The Economic Cost [129] section of this report uses the Medical Expenditures Panel Survey (MEPS), a standard source for cost of illness estimates, to estimate the total direct and indirect costs of musculoskeletal conditions and selected categories of musculoskeletal conditions, as well as the incremental direct and indirect costs specifically attributable to the selected category. Total costs are all costs for a patient regardless of the condition responsible; incremental costs are those costs attributed to a specified condition. A quick review of all economic terms used can be found by clicking HERE [130]. 

There are several important points to remember here. First, for arthritis and other rheumatic conditions, MEPS requires the use of selected 3-digit ICD-9-CM codes, using the 3- and 4-digit NADW AORC ICD-9-CM codes [131] to create a similar category called “arthritis and joint pain.” This approach has been used for a number of years and provides a comparative estimate of the costs of AORC. Additionally, costs estimates are per person and reported as mean per person costs. To arrive at the estimated aggregate cost, the mean per person cost is multiplied by the number of people affected, resulting in a total cost for conditions in the United States.

MEPS provides estimates of actual medical “expenditures,” meaning money changing hands, rather than medical “charges,” which are based on what is originally billed but rarely paid in full. Thus, the term direct costs, as used here, reflects actual medical expenditures. Indirect costs are those associated with lost wages. Aggregate costs for both direct and indirect costs are the sum of per-person costs across all individuals with the condition.

All-cause costs include medical expenditures or lost wages for persons with musculoskeletal disease, regardless of whether those costs are due to the musculoskeletal disease or another medical condition. Incremental costs are those estimated as attributable to musculoskeletal disease.

Direct Costs

Annual all-cause direct costs, in 2014 dollars, for arthritis and joint pain increased from a per person mean of $6,642 in the years 1996-1998 to $9,554 in 2012-2014. Incremental direct costs for arthritis and joint pain increased from a per person mean of $679 in the years 1996-1998 to a mean of $1,352 in 2012-2014, in 2014 dollars. The change in total mean costs was 44%, while incremental mean costs doubled. Incremental arthritis and joint pain costs showed a decline in 2012-2014 annual average costs compared to the previous five periods. (Reference Table 8.4.3 PDF [132] CSV [133]; Table 8.5.3 PDF [134] CSV [135])

Mean per person direct costs include ambulatory care, inpatient care, prescriptions, and other healthcare costs. In 2012-2014, ambulatory care accounted for about a third of per person direct costs, with inpatient care and prescriptions each accounting for approximately one-quarter (28% and 25%, respectively) of total cost. Over the past 18 years, prescription costs have seen the greatest change, rising nearly 140% per person in that time. Both inpatient and other healthcare costs remained steady at 9% and 11% increase, respectively. Ambulatory care increased by 59% over the same time period. (Reference Table 8.4.3 PDF [132] CSV [133])

Annual all-cause aggregate medical costs for persons with a diagnosis of arthritis and joint pain in the US increased from $192.4 billion in 1996-1998 to $626.8 billion, in 2014 dollars, for the years 2012-2014. Aggregate annual direct costs specifically attributed to arthritis and joint pain (incremental costs) in the US increased from $19.7 billion in 1996-1998 to $88.7 billion for the years 2012-2014, in 2014 dollars. While the increase over the 18-year period for total aggregate costs was more than 225%, the increase for incremental aggregate costs was greater than 350%, despite the recent decline in aggregate incremental costs. (Reference Table 8.6.3 PDF [140] CSV [141])

Annual per-person all-cause direct costs for arthritis and joint pain are highest for people age 65 and older, females, non-Hispanic whites, and residents of the Northeast region. Lower education and marital staus (divorced-widowed-separated) are also factors in higher cost. Public only insurance (Medicaid/Medicare) show the highest per person costs, in part because they serve a large share of the elderly population. (Reference Table 8.15.3 PDF [144] CSV [145])

Mean and aggregate total and incremental direct and indirect costs for osteoarthritis [146], rheumatoid arthritis [147], gout [148], and connective tissue disease [149], using the annual average for years 2008-2014 MEPS data, are calculated and shown in their respective sections.

Indirect Costs

“Indirect costs” as used in this report reflect estimates of earnings losses for persons with a work history who are unable to work due to a medical condition. They do not reflect supplemental measures, such as reduced productivity, worker replacement, or early retirement due to medical conditions.

Indirect costs are not estimated for the broad category of arthritis and joint pain.

 

Because many types of arthritis have a higher prevalence among older adults, we expect that the current aging of the population will increase the prevalence and impact of AORC unless new interventions are implemented within the near future. The projections of arthritis prevalence and AAAL take into account age and sex, but do not take into account potentially important factors such as the obesity epidemic and the increasing frequency of joint injuries.1 The age-adjusted percentage of AAAL among adults with arthritis increased 19% between 2002-2004 and 2013-2015.2 Previous costs of arthritis have been driven by age-related increases in prevalence,3 so future costs of arthritis are likely to be driven higher by the same age-related increase in prevalence, but also from the increasing frequency of surgical interventions.

• 1. Hootman JM, Helmick CG. Updated projections of US prevalence of arthritis and associated activity limitations. Arthritis Rheum 2016;68(7):1582-1587.
• 2. Barbour KE, Helmick CG, Boring M, Brady TJ.  Prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation—United States, 2013-2015. MMWR 2017;66(9):246-253.
• 3. Cisternas MG, Murphy L, Yelin E, Foreman AJ, Pasta DJ, Helmick CG. Trends in medical care expenditures of adults with arthritis and other rheumatic conditions: 1997 to 2005. J Rheum 2009;36:2531-8.

Several data limitations exist for monitoring AORC burden in the future. First, on October 1, 2015, ICD-10-CM was required for use in clinical records; it was previously in use for death records. The current National Arthritis Data Workgroup definition of AORC uses ICD-9-CM codes. Due to significant changes in conceptualizing the new codes, a direct translation cannot be made. This means a new definition of AORC or some similar concept will be needed for analyses using ICD-based data in the future. CDC is working with ICD-10-CM translation experts and selected stakeholders to propose a draft standard ICD-10-CM based definition, which will be shared with the larger arthritis community to reach agreement on a new definition.

Second, there is a need for data on more specific conditions, for example rheumatoid arthritis, systemic lupus erythematosus, and psoriatic arthritis, to help drive clinical (eg, treatment, quality of care) and public health (eg, self-management education, safe physical activity) efforts that allow for better incidence estimates in order to better understand risk. Electronic health records may prove helpful in creating valid measures. There is also a lack of data on patient reported outcome measures (PROMs) on pain and function in electronic health records and administrative databases. These outcome measures are important to assessing the impact/burden of rheumatic and musculoskeletal diseases. 

Arthritis and other rheumatic conditions are not addressed with the same priority as many other chronic conditions, perhaps because such priorities are driven more by easily available measures of mortality rather than by more challenging measures such as quality of life, disability, and impact on work. However, there is a growing policy interest in the role of multiple chronic conditions in health and health costs,1 and AORC plays a major role from this perspective for at least three reasons. First, those with priority chronic conditions are highly affected by AORC, with about half of adults with heart disease or diabetes and about a third of adults with obesity affected by DDA.2^,3^,4 Second, arthritis is very common condition among individuals with two or more chronic conditions, regardless of the conditions considered.5 Third, those with arthritis as one of their multiple chronic conditions fare much worse on important life domains such as social participation restriction, serious psychological distress, and work limitations.6

• 1. U.S. Department of Health and Human Services. HHS initiative on multiple chronic conditions. http://www.hhs.gov/ash/initiatives/mcc/ [150]. Accessed October 24, 2018.
• 2. Bolen J, Murphy L, Greenlund K, et. al. Arthritis as a potential barrier to physical activity among adults with heart disease — United States, 2005 and 2007. MMWR 2009;58(7):165-169.
• 3. Bolen J, Hootman J, Helmick CG, et. al. Arthritis as a potential barrier to physical activity among adults with diabetes — United States, 2005 and 2007. MMWR 2008;57(18):486-489.
• 4. Barbour KE, Hootman JM, Murphy LB, Helmick CG. Arthritis as a potential barrier to physical activity among obese adults–United States, 2007 and 2009. MMWR 2011;60(19):614–618.
• 5. Ward BW, Schiller JS. Prevalence of multiple chronic conditions among US adults: estimates from the National Health Interview Survey, 2010. Prev Chronic Dis 2013;10:120203. DOI: http://dx.doi.org/10.5888/pcd10.120203 [151].
• 6. Qin J, Theis KA, Barbour KE, et.al. Impact of arthritis and multiple chronic conditions on selected life domains — United States, 2013. MMWR 2015;64(21):578-582.

There are widespread and consistent professional recommendations for most types of AORC that involve increasing self-management of the disease through education, physical activity, and achieving a healthy weight, but little progress is being made.1 Such behavioral interventions offer evidence-based improvements to patients without the side effects seen with medications and other interventions. While most clinical settings are not set up to help patients achieve these recommendations effectively, increasing clinical/community linkages may offer a better approach. To see if provider referrals to community resources is a better solution, approaches such as the 1.2.3 Approach to Provider Outreach [152] and Spread the Word: Marketing Self-Management Education Through Ambassador Outreach [153] are being pilot tested in communities.
 
The Healthy People [154] project started with the 1979 Surgeon General’s report, Healthy People: The Surgeon General’s Report on Health Promotion and Disease Prevention. The current version of Healthy People 2020 [155] has set nine arthritis objectives for the nation to achieve by 2020, but only limited progress has occurred with the current level of investments in interventions. Currently, four new developmental objectives are included in the Arthritis, Osteoporosis, and Chronic Back Conditions [156] topic area as part of a larger effort to insure that chronic pain, regardless of the original cause, is included in Healthy People 2020.

There is a need for more conveniently measured outcomes that are important to most people. Such outcomes include effects on work, activities, health-related quality of life, independence, and ability to keep doing valued life activities.

Research funding to develop and evaluate more effective clinical and public health interventions is relatively modest, given that arthritis is the most common cause of disability and is a large and growing problem, affecting 54.4 million adults now,2 and a projected 78 million by 2040.3 This is especially frustrating because even the evidence-based interventions we have now are not reaching the people who would benefit from them. Implementation research to translate effective interventions to clinical practice and/or community settings is needed.

Although most adults with doctor-diagnosed arthritis are younger than age 65 and in their working years, the effect of their arthritis on employment and work, and the effect of reasonable workplace accommodations, have not been explored in depth. There is a need for the development and demonstration of web-based or app-based interventions for education, physical activity and achieving a healthy weight. This is an urgent issue right now and will continue to be an urgent issue as an aging workforce keeps working beyond age 65, as is anticipated.

 

 

 

• 1. Office of Disease Prevention and Health Promotion. HealthyPeople.gov.  http://www.healthypeople.gov/2020/data-search/Search-the-DData?&f[0]=field_topic_area%3A3507  [157]  Accessed October 24, 2018.
• 2. Barbour KE, Helmick CG, Boring M, Brady TJ. Vital signs: prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation — United States, 2013–2015. MMWR 2017;66:246–253. DOI: http://dx.doi.org/10.15585/mmwr.mm6609e1 [128]. Accessed July 31, 2017.
• 3. Hootman JM, Helmick CG, Barbour KE, et al. Updated projected prevalence of self-reported doctor-diagnosed arthritis and arthritis-attributable activity limitation among US adults, 2015-2040. Arthritis Rheumatol 2016:68(7):1582-1587.

As noted above, the use of ICD-9-CM codes for clinical and public health purposes ended with the healthcare system shift to the ICD-10-CM codes on October 1, 2015. This means the national surveys analyzed here that use ICD codes will shift to ICD-10CM as well. Standard definitions of generic and specific types of AORC need to be developed for clinical and public health researchers using the new ICD-10-CM codes; otherwise, investments in research will not be comparable and will be unable to build on each other.

Codes used in this analysis of AORC are based on the "National Arthritis Data Workgroup ICD-9-CM diagnostic codes for arthritis and other rheumatic conditions." Centers for Disease Control and Prevention, Arthritis Program, National Arthritis Data Workgroup.1

Osteoarthritis and allied disorders
    715-Osteoarthritis and allied disorders
Rheumatoid arthritis
    714-Rheumatoid arthritis and other inflammatory polyarthropathies
Gout and other crystal arthropathies
    274-Gout
    712-Crystal arthropathies
Joint pain, effusion and other unspecified joint disorders
    716.1, .3-.6-.9-Other unspecified arthropathies
     719.0, .4-.9-Other and unspecified joint disorders
Spondylarthropathies
    720-AS/inflammatory spondylopathies
    721-Spondylosis and allied disorders
    99.3-Reiter’s Disease
    696.0-Psoriatic arthopathy
Fibromyalgia
    729.1-Myalgia and myositis unspecified
Diffuse connective tissue disease
    710-Diffuse connective tissue disease [excl 710.0-.2]
    710.2-Sicca syndrome (also called Sjögren's syndrome)
    710.1-Systemic sclerosis (SSC, scleroderma)
    710.0-Systemic lupus erythematosus (SLE)
Carpal tunnel syndrome
    354.0-Carpal tunnel syndrome
Soft tissue disorders (excluding back)
    726-Peripheral enthesopathies and allied disorders
    727-Other disorders of synovium/tendon/bursa
    728.0-.3, .6–.9-Disorders of muscle/ligament/fascia
    729.0-Rheumatism, unspecified and fibrositis
    729.4-Fascitis, unspecified
Other specified rheumatic conditions
    95.6-Syphilis of muscle
    95.7-Syphilis of synovium/tendon/bursa
    98.5-Gonococcal infection of joint
    136.1-Behcet’s syndrome
    277.2-Other disorders purine/pyrimidine metabolism
    287.0-Allergic purpura
    344.6-Cauda equina syndrome
    353.0-Brachial plexus/thoracic outlet lesions
    355.5-Tarsal tunnel syndrome
    357.1-Polyneuropathy in collagen vascular disease
    390-Rheumatic fever w/o heart disease
    391-Rheumatic fever w/heart disease
    437.4-Cerebral arteritis
    443.0-Raynaud’s syndrome
    446-Polyarteritis nodosa and allied conditions [excl 446.5]
    447.6-Arteritis, unspecified
    711-Arthritis associated with infections
    713-Arthropathy associated w/disorders classified elsewhere
    716.0, .2, .8-Specified arthropathies
    719.2, .3-Specified joint disorders
    725-Polymyalgia rheumatica

• 1. Centers for Disease Control and Prevention. Arthritiiis Case Definitions. http://www.cdc.gov/arthritis/data_statistics/arthritis_codes_2004.pdf [158] ). Accessed October 29, 2013.

Osteoarthritis (OA) is widely recognized as the most common form of arthritis, and a major cause of pain and disability among US adults. Estimates of prevalence vary depending on how OA is defined: radiographic, symptomatic radiographic, or symptomatic only (self-reported presence of pain, aching, or stiffness). Radiographic OA is reported at higher prevalence levels than symptomatic, but symptomatic OA is more often cited from the self-reported databases.

From 2008 to 2014, 32.5 million US adults, or one in seven persons (14%), reported osteoarthritis and allied disorders, including joint pain with other specified or unspecified arthropathy, (herein called “osteoarthritis”) annually. Per previous research on the definition of osteoarthritis in the Medical Expenditure Panel Survey (MEPS),1 OA was defined as the presence of ICD-9-CM code 715 or a self-reported diagnosis of arthritis excluding rheumatoid arthritis and presence of ICD-9-CM 716 or ICD-9-CM 719. (Reference Table 8.13 PDF [164] CSV [165])

Across socio-demographic and health status characteristics, the following five groups represented the largest number of adults with OA by demographic classification: non-Hispanic whites (25.3 million), middle age (45-64 years) (14.8 million) or older adults (≥ 65 years) (13.8 million), those with private insurance (18.8 million), and those who were married/had a partner (17.8 million). (Reference Table 8.22 PDF [166] CSV [167])

However, total numbers do not reflect the share of the population group with OA. For example, females represent about 51% of the adult population in any given year, but comprise 78% of adults with OA. An even more disproportionate share of 18% of the population age 65 and older have OA (43%). This compares to 46% with osteoarthritis in the 34% of the population age 45 to 64 years. Non-Hispanic whites still have the highest share by race/ethnicity, comprising 65% of the population but 78% of those with OA, while Hispanics have the lowest (15% of population to 7% of adults with OA). Geographic region is not a major factor for OA, although the Midwest has a higher proportion of cases than it represents in the US population.

Share of the total OA population, however, does not give the whole picture. Since OA is closely linked to age, race/ethnicity and geographical regions with younger population segments will exhibit a lower overall share of OA patients. Both non-Hispanic black and Hispanic populations have a higher share of adults age 45 and older reporting OA than is found among non-Hispanic white adults. Hence, while non-Hispanic white adults represent the largest group of adults with OA, other race/ethnic groups have higher rates of OA. This same pattern can be seen in geographic regions, where the West has a younger population but higher rate of OA in the 65 and older population than is found in other regions. (Reference Table T3A.1.1.a PDF [172] CSV [173])

Joint Involvement in Osteoarthritis

Most OA diagnoses in both a hospital and outpatient setting do not specify the bodily site for which a healthcare visit is made. However, among those that are diagnosed with a specific site, the knee is the most common, followed by the hip. The knee accounts for about one-third (31%) of OA visits in all settings and is the only site identified in the data that meets reliability standards in all outpatient settings. Osteoarthritis in the hip accounts for 14% of hospital discharges, and 6% of physician office visits. (Reference Table 3C.1.0 PDF [176] CSV [177])

 

Healthcare Utilization

Osteoarthritis was diagnosed in 23.7 million healthcare visits in 2013, or 2.4% of all healthcare visits for any cause (Reference Table 3A.3.0.1 PDF [14] CSV [15]). It accounted for 10% of all hospitalizations and 2% of ambulatory visits.

Hospitalization

Nearly 3 million hospital stays in 2013 had an OA diagnosis and it was the leading cause (46%) of hospitalization among all arthritis diagnoses. Osteoarthritis accounted for 45% of total hospital charges for arthritis diagnoses (cost charged but not necessarily paid), presumably in part because OA is the principal diagnosis associated with hip and knee joint replacements. Fewer than half (43%) of patients with an OA diagnosis were discharged to home or self-care, the lowest share of all arthritis diagnosed hospitalized patients. This is probably due to discharges to assisted living facilities or skilled nursing homes for rehabilitation following the hip or knee joint replacement. (Reference Table 3A.3.0.1 PDF [14] CSV [15]; Table 3A.3.1.1.1 PDF [38] CSV [39]; Table 3A.3.1.3.1 PDF [51] CSV [52]; and Table 3A.5.3 PDF [178]CSV [179])

Females hospitalized with OA outnumber males two to one, while two in three patients were age 65 and older and hospitalized at a rate of 4.5 in 100. Non-Hispanic whites had the highest rate of hospitalization for OA (1.4 in 100 persons), while Hispanics had the lowest rate (0.4/100). Residents of the Midwest region were also more likely to be hospitalized with a diagnosis of OA (1.5/100), while those living in the West were least likely (0.9/100). Regional differences are a product of age to some degree, with the mean age of the Northeast and Midwest about 4 years older than the West. (Reference Table 3A.3.1.0.1 PDF [26] CSV [27]; Table 3A.3.1.0.2 PDF [28] CSV [29]; Table 3A.3.1.0.3 PDF [30] CSV [31]; and Table 3A.3.1.0.4 PDF [32] CSV [33])

Ambulatory Care Visits

Osteoarthritis was diagnosed in 20.8 million outpatient visits in 2013 and accounted for one in five (21%) ambulatory care visits with any arthritis diagnosis. This was a rate of 1 in 12 (8.4%) outpatient visits for any diagnoses including an OA diagnosis. Visits per 100 were higher among females, adults 45 years and older, and non-Hispanic whites and blacks. Residents in the South had the lowest rate of outpatient visits for OA. (Reference Table 3A.3.2.0.1 PDF [61] CSV [62]; Table 3A.3.2.0.2 PDF [63] CSV [64]; Table 3A.3.2.0.3 PDF [65] CSV [66]; Table 3A.3.2.0.4 PDF [67] CSV [68])

Economic Burden

Combining direct and indirect costs for OA and allied disorders, average annual all-cause costs for the years 2008-2014 were $486.4 billion. Total incremental costs (direct and indirect costs directly associated with osteoarthritis) were $136.8 billion. (Reference Table 8.13 PDF [164] CSV [165])

Direct Medical Costs

Among all adults with osteoarthritis, annual all-cause per person direct costs were $11,502. Those reporting limitations had the highest all-cause per person direct costs: any limitation in work, housework, or school activities ($17,136) or any limitation in IADLs, ADLs, functioning, work, housework, school, vision or hearing ($14,146).

Annual total all-cause direct costs were $373.2 billion.  The five socio-demographic groups with the highest total all-cause direct costs were: non-Hispanic whites ($300.7 billion); those with any limitation in IADLs, ADLs, functioning, work, housework, school, vision or hearing ($298.5 billion); any limitation in work, housework, or school activities ($213.0 billion); any private insurance ($216.5 billion); or who were married/had a partner ($200.4 billion).

Osteoarthritis incremental direct medical costs totaled $65.5 billion annually; average per person OA incremental costs were $2,018. (Reference Table 8.13 PDF [164] CSV [165], and Table 8.22 PDF [166] CSV [167])

Indirect Costs

Some 16.7 million adults of working age (18-64 years) with a work history had OA. The ratio of persons in the labor force without osteoarthritis (90%) is higher than for those with OA (69%), resulting in earnings losses due to OA.

On average, for the years 2008-2014, those without OA earned $6,783 more than those with OA, which represented a total of $113.2 billion in all-cause earnings losses for all U.S. adults with OA. Earnings losses attributable to OA were $71.3 billion; per person osteoarthritis-attributable earnings losses were $4,274. (Reference Table 8.13 PDF [164] CSV [165])

Lifetime OA Treatment Costs

Lifetime cost attributed to knee OA in 2013 were $140,300. More than one-half (54%) of knee OA patients underwent total knee arthroplasty (TKA) an average of 13 years after diagnosis. The largest proportion of knee OA-related direct medical costs for those meeting TKA eligibility criteria was attributable to primary TKA.2

• 1. Cisternas MG, Murphy L, Sacks JJ, Solomon DH, et al. Alternative methods for defining osteoarthritis and the impact on estimating prevalence in a US population-based survey. Arthritis Care Res 2016;68(5):574-580.
• 2. Losina E, Paltiel AD, Weinstein AM, et al. Lifetime medical costs of knee osteoarthritis management in the United States: impact of extending indications for total knee arthroplasty. Arthritis Care Res (Hoboken) 2015;67(2):203-215.

Inflammatory arthritis is a group of diseases characterized by inflammation of the synovial membrane in the joints and, often, other tissues throughout the body. Some forms of inflammatory arthritis are autoimmune diseases, conditions in which the body’s immune system attacks healthy tissue, also known as systemic autoimmune rheumatic diseases (SARD). Examples of SARDs that cause inflammatory arthritis include rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjögren’s syndrome (SjS), systemic sclerosis (SSc), polymyositis (PM), and dermatomyositis (DM). Other types of inflammatory arthritis include axial spondyloarthritis (formerly called ankylosing spondylitis) and psoriatic arthritis, along with gout which is also considered a metabolic arthritis and discussed under it's own heading.

As a group, inflammatory arthritic diseases are characterized by joint pain, swelling, warmth, and tenderness in joints, and can cause deformity and loss of function of affected joints.  Since these diseases are systemic, they may be associated with involvement of other tissues or organs including the skin, eye and bowel. In addition, in these diseases, blood tests provide evidence of inflammation and some conditions are useful markers that assess disease likelihood. Inflammatory arthritis conditions are sometimes difficult to diagnose and distinguish; all patients suspected of having an inflammatory arthritis should be referred to a rheumatologist for evaluation and management. Arthritis occurring in children and adolescents is referred to as juvenile idiopathic arthritis (formerly juvenile rheumatoid arthritis) and is discussed in the Juvenile Arthritis [11] heading.

Only the most common inflammatory arthritides will be discussed below. A listing of the many types of inflammatory arthritis and related conditions can be seen by clicking HERE [186].

Gout is caused by a buildup in the body of uric acid, in the form of monosodium urate crystals that the body cannot rid itself of quickly. This condition is characterized by hyperuricemia, referring to an elevation in the serum level of uric acid. It is not fully understood why some people with hyperuricemia develop gout and others do not. Gout is characterized by recurrent attacks of painful, red, tender, warm, and swollen joints, which generally affects only one joint at a time, often the large toe. It is more common in men, but also affects women after menopause. Repeated flares of gout can lead to chronic gouty arthritis, with involvement of multiple joints and the development of subcutaneous nodules, called tophi.  While gout can be an intermittent condition, it can also lead to severe chronic arthritis and joint damage and deformity. Gout occurs frequently in patients with what is termed the metabolic syndrome and affects patients who also have diabetes, hypertension, and obesity.

Other crystal arthropathies can be caused by deposits of calcium pyrophosphate dihydrate (CPPD) crystals in the joints and have symptoms similar to gout. CPPD deposition disease is less common than gout, although radiographic chondrocalcinosis is common in older adults.

Prevalence of Gout

Prevalence estimates of gout vary for the US from 1% - 4%, depending on the data source and time frame. In 2005, an estimated 6.1 million adults reported having gout at some time, with 3.0 million affected each year.1 Estimates from the MEPS analyzed for the economic data section reported  3.1 million US adults had gout annually for the years 2008-2012, an annual prevalence rate of 1.3%.(Reference Table 8.13 PDF [164] CSV [165] and Table 8.24 PDF [239] CSV [240]) Additional studies report a higher prevalence of 3.9%, or 8.3 million adults in 2007-2008, using the NHANES as the basis of estimates.2^,3^,4 Another NHANES study from 2007-2010 reported a prevalence of 3.8%.5 Overall, it is believed the prevalence of gout is rising, with obesity and hypertension cited as contributors.2^,4 A study of hospitalization trends using the NIS from 1993-2011 supported this, showing hospitalizations with a diagnosis of rheumatoid arthritis declining over the study period while diagnosis of gout was reported as increasing.6

Prevalence of gout is higher in males than in females, 5.9% to 2.0%, respectively,4 or at a ratio of 3-4:1. The incidence of gout increases with age, and was shown in the MEPS to be higher in the following select socio-demographic groups: non-Hispanic whites (2.3 of 3.1 million); married/had a partner (1.9 million); any private insurance (2.0 million); those with any limitation in IADLs, ADLs, functioning, work, housework, school, vision, or hearing (1.7 million). (Reference Table 8.24 PDF [239] CSV [240]).

 

Healthcare Utilization

Hospitalization

More than 850,000 hospitalizations in 2013 had a diagnosis of gout, representing 2.9% of hospitals visits for any diagnoses, and accounting for 3.3% of all hospital charges billed. Gout is diagnosed along with joint pain and soft tissue disorders when multiple diagnoses are made (7% and 3.5% cross-diagnosis, respectively). At discharge, patients diagnosed with gout are more likely to be transferred to short-term or home health care than those with any diagnoses (45% vs 31%). (Reference Table 3A.3.1.0.1 PDF [26] CSV [27]; Table 3A.3.0.2 PDF [18] CSV [19]; Table 3A.3.1.1.1 PDF [38] CSV [39]; Table 3A.3.1.3.1 PDF [51] CSV [52])

 

Ambulatory Care Visits

Gout diagnoses were made in only 0.5% of ambulatory care visits for any diagnosis, accounting for 5.3 million ambulatory visits. Ambulatory visits were made more frequently by males (72%), those aged 65 years and older (50%), non-Hispanic whites (59%), and by those living in the Northeast (rate of 2.8/100 persons versus 2.1/100 for all regions). (Reference Table 3A.3.2.0.1 PDF [61] CSV [62]; Table 3A.3.2.0.2 PDF [63] CSV [64]; Table 3A.3.2.0.3 PDF [65] CSV [66]; and Table 3A.3.2.0.4 PDF [67] CSV [68])

 

Economic Burden

Estimates for gout, defined as ICD-9-CM 274, were generated from 2008-2012 MEPS data; analysis was limited to those years because the ICD-9-CM code for gout was suppressed in 2013 and 2014 MEPS data. Combining direct and indirect costs for gout, total average costs annually for the years 2008-2012 were $26 billion. Incremental costs could not be calculated due to a small sample size. (Reference Table 8.13 PDF [164] CSV [165])

 

Direct Costs

Among all adults with gout, all-cause per person direct costs were $11,936. Those with any limitation in work, housework, or school activities had the highest all-cause per person direct costs ($16,843) whereas those age 18-44 years had the lowest ($5,934). Total all-cause direct costs were $36.6 million.  Direct costs attributable to gout were not reported because the relative standard errors for the estimates was greater than 30%. (Reference Table 8.13 PDF [164] CSV [165] and Table 8.24 PDF [239] CSV [240])

 

Indirect Costs

The percentage working during the year among adults age 18-64 years was similar for those with (85%) and without gout (88%). Per person, those with gout earned $6,810 more than those without gout; thus, overall, those with gout had negative earnings losses (aggregate of -10.0 billion). Like direct costs, earnings losses attributable to gout were not reported because the estimates were unreliable, with a relative standard error greater than 30%. (Reference Table 8.13 PDF [164] CSV [165]).

 

• 1. Lawrence RC, Felson DT, Helmick CG, et al for the National Arthritis Data Workgroup. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States:  Part II. Arthritis & Rheumatism 2008;58(1):26-35.
• 2. a. b. Gadol N. Global burden of gout: prevalence and risk factors. https://www.medpagetoday.com/resource-center/Gout/Global-Burden/a/54489 [247] . Accessed September 25, 2017.
• 3. Dalbeth N, Merriman TR, Stamp LK. Gout. Lancet 2016:355(10055);2039-2052.
• 4. a. b. c. Zhu Y, Pandya BJ, Choi HK. The National Health and Nutrition Examination Survey 2007-2008. Arth & Rheum 2011:63(10);3136-3141. Doi 10.1002/art.30520.
• 5. Lim SY, Lu N, Oza A, et al. Trends in gout and rheumatoid arthritis hospitalizations in the United States, 1993-2011. JAMA. 2016:315(21);2345-2346.
• 6. Roddy E, Choi H. Epidemiology of gout. Rheum Dis Clin North Am. 2014:40(2);155-175. Doi: 10.1016/j.rdc.2014.01.001.

Arthritis from joint infection, known by the umbrella term as septic arthritis, can occur from an infection anywhere in the body traveling through the bloodstream. It can also occur from a penetrating injury that delivers germs directly to a joint. An infected joint is usually very tender, swollen, and painful. When caught early and treated with antibiotics it can be cleared of the joint infection. Surgical drainage of the infected joint is often necessary which can be performed arthroscopically. In some cases, the arthritis becomes chronic. Knees are most commonly affected, but septic arthritis also can affect hips, shoulders, and other joints. Often, an infected joint has been affected by another form of arthritis. Gonococcal septic arthritis, transmitted from gonorrhea bacterium, a sexually transmitted disease, can occur in otherwise healthy individuals. Lyme disease is another form of arthritis associated with infection and occurs in certain areas of the country.

The incidence of septic arthritis in industrialized countries, including the US, is estimated at six (2-10) per 100,000 population per year. In persons with underlying joint disease or prosthetic joints, incidence increases to 6-30 per 100,000 per year. The most susceptible populations are young children and the elderly.1 Infection can occur in a prosthetic joint and be a source of chronic pain. Biologics, while shown to work well for RA and other inflammatory arthritis pain, have also been associated with statistically significant higher rates of serious infections as they are designed to weaken the immune system. Serious infections included opportunistic infections as well as bacterial infections in most studies.2 These side effects of increased risk for septic arthritis are recognized and published in numerous sources.

Septic arthritis is included in the “other specific rheumatic conditions” in the AORC discussion.

• 1. Lynn MM, Mathews CJ. Advances in the management of bacterial septic arthritis. International Journal of Clinical Rheumatology 2012;7(3):335-342.
• 2. Singh JA, Wells GA, Christensen R, et al. Adverse effects of biologics: a network meta-analysis and Cochrane overview. Cochrane Library. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD008794.pub2/abstra... [248] Accessed October 24, 2017.

Fibromyalgia does not fit within the main arthritis classifications but is considered a chronic pain condition. The primary symptoms are widespread pain throughout the body and fatigue. Recent revisions to diagnosis now focus on four criteria.1  
1)    Generalized pain, defined as pain in at least 4 of 5 regions is present.
2)    Symptoms have been present at a similar level for at least 3 months.
3)    Widespread pain index (WPI) ≥7 and symptom severity scale (SSS) score ≥5 OR WPI of 4-6 and SSS score ≥9.
4)    A diagnosis of fibromyalgia is valid irrespective of other diagnoses. A diagnosis of fibromyalgia does not exclude the presence of other clinically important illnesses.

The cause of fibromyalgia is not known, but current theories include a higher sensitivity to pain. Fibromyalgia can occur by itself, although it can also accompany another form of arthritis such as rheumatoid arthritis or spondyloarthritis.

 

Prevalence of Fibromyalgia

Estimates of fibromyalgia range from 4 million (2% of the adult population)2 to 10 million (5% of adult population).3 Fibromyalgia is most prevalent in females, with up to 90% of incident cases females. It is also more common among older members of the population.

 
Healthcare Utilization

Hospitalization

Just under one-half million (442,000) hospitalizations in 2013 had a diagnosis of fibromyalgia, representing 1.5% of hospital visits for any diagnoses, and accounting for 1.4% of all hospital charges billed. Females accounted for 89% of the hospitalizations, with those age 45 to 64 accounting for nearly half (48%) of the discharges. Fibromyalgia is diagnosed along with connective tissue disease (11.1%), joint pain (8.2%), and rheumatoid arthritis (7.1%) when multiple diagnoses are made. Hospital stays are similar to discharges for any diagnoses in length of stay and mean charges. Discharge to home is most common.  (Reference Table 3A.3.1.0.1 PDF [26] CSV [27]; Table 3A.3.1.0.2 PDF [28] CSV [29]; Table 3A.3.0.2 PDF [18] CSV [19]; Table 3A.3.1.1.1 PDF [38] CSV [39]; Table 3A.3.1.3.1 PDF [51] CSV [52])

 

Ambulatory Care Visits

Fibromyalgia diagnoses were made in 0.8% of all ambulatory care visits for any diagnosis, accounting for 7.7 million ambulatory visits. Ambulatory visits were made more frequently by females (79%), those aged 45-64 years (52%), non-Hispanic whites (74%), and by those living in the Northeast region (rate of 3.8/100 persons versus 3.1/100 for all regions). (Reference Table 3A.3.2.0.1 PDF [61] CSV [62]; Table 3A.3.2.0.2 PDF [63] CSV [64]; Table 3A.3.2.0.3 PDF [65] CSV [66]; and Table 3A.3.2.0.4 PDF [67] CSV [68])

Economic Burden

Economic costs were not calculated for fibromyalgia.

• 1. Wolfe F, Clauw DJ, Fitzcharles MA, et al. 2016 revisions to the 1010/2011 fibromyalgia diagnostic criteria. Seminars in Arthritis Rheum 2016;46(3):319-329.
• 2. Center for Disease Control. Fibromyalgia.  https://www.cdc.gov/arthritis/basics/fibromyalgia.htm [251] . Accessed September 25, 2017.
• 3. National Fibromyalgia Association. About fibromyalgia. http://www.fmaware.org/about-fibromyalgia/prevalence/ [252]. Accessed September 25, 2017.

Juvenile arthritis (JA) is an umbrella term used to describe a number of autoimmune and inflammatory conditions that can develop in children. It is the most common rheumatic disease of childhood, particularly in the Western world, with children of European descent reporting higher incidence rates.1^,2

The most common form of JA is Juvenile Idiopathic Arthritis (JIA) (formally called juvenile rheumatoid arthritis (JRA) or Juvenile Chronic Arthritis (JCA)). JIA is diagnosed in a child <16 years of age with at least six weeks of persistent arthritis. There are seven distinct subtypes, each having a different presentation and association to autoimmunity and genetics.3 Subtypes also differ in typical age of onset. Certain subtypes are associated with an increased risk of inflammatory eye disease (uveitis).

Understanding the differences in the various forms of JIA, their causes, and methods to better diagnose and treat these conditions in children is important to future treatment and prevention. Among all subtypes, 40% to 45% of children with JIA still have active disease after 10 years.4

Prevalence Of Juvenile Arthritis

Due to the various forms of JA, estimates of prevalence and incidence are difficult to ascertain. Overall estimates are that 294,000 children in the United States have arthritis or another rheumatic disease.5

In 2006, the CDC Arthritis Program finalized a case definition for ongoing surveillance of significant pediatric arthritis and other rheumatologic conditions (SPARC [253]) using the current ICD-9-CM diagnostically based data systems. In response to the variations in conditions that some felt should be included, but were not, CDC generated estimates for conditions that were not included in the case definition but were felt by some should have been.

Healthcare Utilization

Hospitalization for JA

Using the SPARC definitions, analysis of the recent national healthcare database focusing on children, the Healthcare Cost and Utility Project (HCUP) KID, showed 104,400 children age 17 and younger were discharged from a hospital with any diagnosis of SPARC in 2012. Of those, 15,600, or 15%, had an admitting diagnosis of SPARC. Slightly more females than males were hospitalized; children age 6 and younger were more likely to be hospitalized with an admitting diagnosis of SPARC than older children, accounting for 40% of admissions.

Only a small number of children (3.8%) discharged with any diagnosis of SPARC had a diagnosis of juvenile arthritis. Females accounted for 72% of discharges with a diagnosis of JIA, with 62% of the discharges for children age 13 to 17 years.

Average hospital stays of eight days were found for any diagnosis of SPARC. The very youngest children, babies under age one, had much longer stays and higher mean hospital charges. Children with a diagnosis of JIA had hospital stays of a mean of 4.6 days, with subsequently lower mean charges.

Total hospital charges associated with any diagnoses of SPARC in the population younger than age 20 were $8.3 billion in 2012. (Reference Table 3B.1 PDF [254] CSV [255])

JA Ambulatory Care Visits

Emergency rooms saw 515,600 patients ages 0 to 17 with any diagnoses of SPARC in 2013. Among these patients, 6,900 had a primary diagnosis of JIA. Visits did not show major differences by sex or age.

Due to smaller sample sizes in the currently available databases for physician office visits and outpatient clinics, outpatient visits for a diagnosis of SPARC in the juvenile population are difficult to quantify. In 2013, physician visits for treatment of JA numbered 1.2 million. As with ED visits, major differences by sex or age were not seen. Due to small sample sizes, the number of visits with a diagnosis of JIA was unreliable.

Outpatient clinics saw 305,100 patients in 2011, the most recent year for outpatient data available. Patterns for distribution reflected that of other treatment sites. Due to small sample sizes, the number of visits with a diagnosis of JIA was unreliable.

From these data, an estimated 2.03 million outpatient visits for any diagnoses of SPARC occurred in the 0 to 17 years age population in 2013. (Reference Table 3B.1 PDF [254] CSV [255])

 

ICD-9-CM Codes for SPARC    

In 2006, the CDC Arthritis Program finalized a case definition for ongoing surveillance of significant pediatric arthritis and other rheumatologic conditions (SPARC) using the current ICD-9-CM diagnostically-based data systems.

099.3 - Reactive arthritis
136.1 - Behcet's syndrome
274 - Gout
277.3 - Amyloidosis (includes Familial Mediterranean Fever)
287.0 - Allergic purpura / Henoch Schonlein purpura
390 - Rheumatic fever without heart involvement
391 - Rheumatic fever with heart involvement
437.4 - Cerebral arteritis
443.0 - Raynaud's syndrome
446 - Polyarteritis nodosa and allied conditions
447.6 - Arteritis, unspecified
695.2 - Erythema nodosum
696.0 - Psoriatic arthropathy
701.0 - Linear scleroderma / Circumscribed scleroderma / Morphea
710 - Diffuse diseases of connective tissue
711 - Arthropathy associated with infections
712 - Crystal arthropathies
713 - Arthropathy associated with other disorders classified elsewhere
714 - Rheumatoid arthritis and other inflammatory polyarthropathies
715 - Osteoarthritis and allied disorders
716 - Other and unspecified arthropathies
719.2 - Villonodular synovitis
719.3 - Palindromic rheumatism
720 - Ankylosing spondylitis and other inflammatory spondylopathies
727.0 - Tenosynovitis
729.0 - Rheumatism, unspecified and fibrositis
729.1 - Myalgia and myositis, unspecified

 

• 1. Saurenmann RK, Rose JB ,Tyrrell P, et. al. Epidemiology of juvenile idiopathic arthritis in a multiethnic cohort. Arthritis & Rheumatism. 2007;56(6):1974–1984.  DOI 10.1002/art.22709.
• 2. Espinosa M, Gottlieb BS. Juvenile Idiopathic Arthritis. Pediatrics in Review 2012;33:303-13.
• 3. Petty RE, Southwood TR, Manners P, et al. for the International League of Associations for Rheumatology. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton, 2001. J Rheumatol. 2004 Feb;31(2):390-2.
• 4. Arthritis Foundation (http://www.arthritis.org/arthritis-facts/disease-center/juvenile-arthrit... [260]) November 11, 2014.
• 5. Centers for Disease Control and Prevention (CDC). What is juvenile arthritis?  (https://www.niams.nih.gov/Health_Info/Juv_Arthritis/juvenile_arthritis_f... [261] ) Accessed March 22, 2017.

Joint pain is a major symptom of arthritis and non-arthritis conditions and a primary reason for seeing a medical care provider. Self-report surveys ask about joint pain but do not distinguish the cause of joint pain, which may be from arthritis, injuries, or degeneration of bone surfaces.  

In 2013-2015, chronic joint pain was self-reported in the National Health Interview Survey (NHIS) by 78.9 million adults, among which 40.2 million also reported doctor-diagnosed arthritis (DDA) and 29.1 million reported activity limitations due to arthritis (AAAL). Because the latter two groups are not mutually exclusive, 30.4 million, or about 13% of the total population, have chronic joint pain but no DDA or AAAL. (Reference Table 3A.2.0 PDF [262] CSV [263])

The most common site of chronic joint pain reported by adults with DDA is the knee, reported by nearly 1 in 2 adults. Pain in the shoulder, finger, and/or hip is reported at each site by more than 1 in 4 adults with DDA. While 40% of people with DDA report joint pain in only one site, more than 20% report pain in four or more sites. (Reference Table 3A.2.1.1 PDF [264] CSV [265] and Table 3A.2.1.5 PDF [266] CSV [267])

Among adults with DDA, joint pain occurs in females more frequently than males, and in middle age more frequently than younger or older ages. Joint pain was similar by race/ethnicity and region. (Reference Table 3A.2.1.1 PDF [264] CSV [265]; Table 3A.2.1.2 PDF [268] CSV [269]; Table 3A2.1.3; PDF [270] CSV [271]; and Table 3A.2.1.4 PDF [272] CSV [273])

 

Joint Replacement

While in some sense, the need for a joint replacement represents failure of measures to prevent the occurrence or progression of joint problems, for those with the severe pain or poor function of end-stage joint problems, it can offer a life-altering “cure.” Joint replacements represent one of the fastest growing procedures in the US. Joint replacement procedures for hips and knees are most common, but replacements have been expanding to other joint sites in recent years.

Estimates presented come from the Healthcare Cost and Utility Project (HCUP) Nationwide Inpatient Sample (NIS). In previous editions of BMUS, estimates from the National Hospital Discharge Survey (NHDS) were also presented and are found in two tables showing trends on mean age of joint replacement patients and average length of hospital stay. The NHDS is no longer produced and not otherwise used here.

In 2013, an estimated 1.3 million inpatient joint replacement procedures were performed. Joint replacement procedures comprised about 3.6% of all inpatient procedures. More joint replacements were performed on women than men (60% vs 40%), and 95% of the procedures were performed on knees or hips. (Reference Table 3A.5.1.1 PDF [276] CSV [277])

While joint replacement procedures are being performed on younger patients than in the past, it is still primarily a procedure for older patients. Persons age 65 years and older comprised 14% of the population in 2013 but accounted for 59% of the joint replacement procedures performed; most of the rest were performed among those aged 45 to 64 years. Nearly one in every 60 persons in the 65 years and older population had a joint replacement procedure performed in 2013, although a small number may have had more than one procedure. (Reference Table 3A.5.1.2 PDF [280] CSV [281])  Non-Hispanic whites are more than twice as likely to undergo a joint replacement as those of other racial/ethnic groups. A greater proportion of residents of the Midwest have joint replacements (0.5/100 persons) than residents in other regions of the US. (Reference Table 3A.5.1.3 PDF [282] CSV [283]; and Table 3A.5.1.4 PDF [284] CSV [285])

Knee Replacement Procedures  

In 2013, nearly 723,000 knee replacement procedures were performed in the U.S., comprising 56% of all joint replacement procedures. Over 90% were total knee replacements, but 8% were revision knee replacements, which occur when the original replacement fails or becomes infected. Three in five knee replacements (62%) occurred in females. More than one-half (57%) of knee replacement procedures were performed on those aged 65 years and older, but a substantial proportion (41%) were performed on persons aged 45 to 64 years. The majority (77%) of knee replacements were performed on non-Hispanic whites, with a proportion more than twice that of other racial/ethnic groups. The ratio of knee replacements to total population is higher in the Midwest region (27.2% of replacements vs. 21.4% of population) than other regions, with the Northeast having the lowest ratio of procedures (16.9% vs. 17.7%). (Reference Table 3A.5.1.1 PDF [276] CSV [277]; Table 3A.5.1.2 PDF [280] CSV [281]; Table 3A.5.1.3 PDF [282] CSV [283]; and Table 3A.5.1.4 PDF [284] CSV [285])

Trends in knee replacement procedures from 1992 to 2013 show steady increases in both total and revision knee replacements. Over the 22-year period, knee replacement procedures more than tripled, with the ratio of revisions to total remaining constant at 8% to 10%. (Reference Table 3A.5.2 PDF [286] CSV [287]).

The principal or first diagnosis associated with total knee replacement is osteoarthritis, accounting for 98% of all replacements in 2013. (Reference Table 3A.5.3 PDF [178] CSV [179]).

The 22-year mean age from 1992 to 2013 was nearly 68 years for total knee replacements, and about half a year younger for revision knee replacements. The mean age for both procedures shows a slow decline over time. (Reference Table 3A.5.4 PDF [290] CSV [291])

The average inpatient length of stay for total knee replacements has shown a remarkable decline of about 67% from a mean of nearly 8.9 days in 1992 to a mean of 3.4 days in 2013. (Reference Table 3A.5.5 PDF [292] CSV [293]).

Despite shorter hospital stays, the mean hospital charges from 1998 through 2013 showed a steady increase for all knee replacements, with revision knee replacement being more expensive than total knee replacement. Total hospitalization charges for both types of knee replacements have increased by five times over (in constant 2013 dollars) from $8.4 billion in 1998 to $41.7 billion in 2013. (Reference Table 3A.5.6 PDF [296] CSV [297])

Most adults (72%) with knee replacements are discharged to either short- or long-term care or home health care, likely due to the short hospital stay. Among persons aged 65 and older, a slightly higher proportion are discharged to either short- or long-term care or home health care (77%). (Reference Table 3A.5.7 PDF [300] CSV [301])  

Hip Replacement Procedures

An estimated 493,700 hip replacement procedures were performed in 2013, comprising 39% of all joint replacement procedures. A majority, about 58%, occurred in females. Total hip replacements occurred three times as frequently as partial hip replacements, and both are far more common than revision hip replacement. A very small number of procedures, about 3,700 in 2013, were hip resurfacing, an alternative to replacement, particularly for young, active males. Females have more hip replacement procedures than males, particularly partial replacements. Hip replacements were more common among adults aged 65 years and older (61%), with most of the rest occurring among adults aged 45 to 64 years. Hip replacements by race/ethnicity paralleled that for all joint replacements, as did hip replacements by geographic region. (Reference Table 3A.5.1.1 PDF [276] CSV [277]; Table 3A.5.1.2 PDF [280] CSV [281]; Table 3A.5.1.3 PDF [282] CSV [283]; and Table 3A.5.1.4 PDF [284] CSV [285])

Trends in hip replacement procedures from 1992 to 2013 show total hip replacements increasing in number by 150%, while the number of partial replacements remained relatively stable. The ratio of revision hip to total hip replacements was about 20% from 1992 to 2002, but has consistently been around 17% since then, and dropped to 15% in 2013. (Reference Table 3A.5.2 PDF [286] CSV [287])

The principal or first listed diagnosis associated with total hip replacements was osteoarthritis (87%).   The primary diagnosis for partial hip replacements was fractures (94%). (Reference Table 3A.5.3 PDF [178] CSV [179])

The 22-year mean age was about 66 years for total hip replacements and 77 years for partial hip replacements, reflecting the different underlying diagnoses. Mean ages for both procedures show a slight decline over the time period, reflecting the younger age at which joint replacements are now considered. However, in 2013, the mean age for partial hip replacements jumped to 80. (Reference Table 3A.5.4 PDF [290] CSV [291])  

The mean length of stay for total hip replacements (3.0 days in 2013) showed the same remarkable decline as that for knee replacements--about 67% from 1992 through 2013. The mean lenth- of-stays for partial and revision replacements are longer, with about a 50% decline over the 22-year period. (Reference Table 3A.5.5 PDF [292] CSV [293])

Despite shorter hospital stays, mean hospital charges from 1998 through 2013 steadily increased for all hip replacements even when compared in constant 2013 dollars. Revision hip replacements are the most expensive, while total hip replacements are the least expensive. Total hospital charges for all hip replacements have tripled (in constant 2013 dollars) from $9.25 billion in 1998 to $30.7 billion in 2013, led by charges for total hip replacements. (Reference Table 3A.5.6 PDF [296] CSV [297])

 

Other Joint Replacement Procedures

Shoulder replacement procedures accounted for an estimated 45,000 procedures in 2013, comprising about 4% of all joint replacement procedures. At the same time, an estimated 19,000 other joint replacement procedures were performed for other joints in the upper and lower extremities, and the spine. More than with hip and knee replacements, these other joint replacement procedures occurred somewhat equally between females and males, and were more evenly divided between those aged 44 to 64 and those aged 65 years and older, except for shoulder replacements. Race/ethnicity and geographic regions resembled the distribution of all joint replacements. (Reference Table 3A.5.1.1 PDF [276] CSV [277]; Table 3A.5.1.2 PDF [280] CSV [281]; Table 3A.5.1.3 PDF [282] CSV [283]; and Table 3A.5.1.4 PDF [284] CSV [285])

A recent study released by the CDC Arthritis Workgroup1 reported state-level arthritis prevalence estimates for the first time. Using the 2015 Behavioral Risk Factor Surveillance System (BRFSS) self-reported doctor-diagnosed data, age-adjusted for comparison across states, the median prevalence among adults across the 50 states and District of Columbia was 23.0%. State prevalence ranged from 17.2% in Hawaii to 33.6% in West Virginia. When viewed by states in the four regions used in this report, 75% of states in the South had an age-adjusted prevalence rate above that of the national rate of 23.0%. This compares to 40% in the Northeast, 42% in the Midwest, and 31% in the West. Furthermore, five states in the South (West Virginia, Alabama, Tennessee, Kentucky, and Arkansas) and two in the Midwest (Michigan and Missouri) had a majority of counties with an arthritis prevalence rate in the highest quartile (31.2%-42.7%). A summary of state age-adjusted doctor-diagnosed arthritis prevalence rates can be found by clicking HERE [310].

The study also looked at doctor-diagnosed arthritis prevalence among adults with three comorbid conditions. At 44.5%, prevalence of arthritis was highest among those with coronary heart disease. This was followed by adults with diabetes (37.3%) and obesity (30.9%).

Leisure-time physical inactivity was also analyzed, and the median age-standardized percentage of inactive adults with arthritis was 35.0%. States in the western region tended to have the lowest prevalence of leisure-time physical inactivity with arthritis, while states in Appalachia and along the Ohio and Mississippi Rivers had the highest percentage of leisure-time physical inactivity, following the overall state prevalence rates for arthritis.

Findings from this study showed that estimated prevalence of arthritis varies by geographic area, with correlation to comorbid conditions and negative health-related characteristics. While direct causation cannot be made and further study is needed to understand why these geographic differences occur, the authors have postulated that known risk factors for arthritis such as comorbid conditions, occupation, socioeconomic status, and negative health-related characteristics may contribute. Access to medical care and medications may also be factors.

The full study of arthritis prevalence by state can be found at https://www.cdc.gov/arthritis/data_statistics/state-data-current.htm [311].

The CDC has also produced estimates of arthritis prevalence by race/ethnicity2 based on the NHIS 2013-2015 data. The lowest prevalence rate was found among non-Hispanic Asians (11.8%), with non-Hispanic multi-racial adults having the highest rate (25.2%). Among adults with arthritis, non-Hispanic Asians also reported the lowest prevalence of arthritis-attributable activity limitations (37.6%), while American Indian/Alaska Natives reported the highest prevalence of limitations (51.5%).

 

Access to Care

While medical professionals in many specialities and with a range of credentials treat patients with arthritis, those specializing in rheumatology are often at the frontline. A recently published workforce study by the American College of Rheumatology highlighted significant disparities in access to care within geographic regions of the US. Their findings showed access to care (defined as the ratio of adult rheumatology physicians to adult population) to be easiest in the Northeast (26,677 ratio) and most difficult in the Southern states (66,163 in the Southwest and 60,087 in the Southeast). This compares to a national average of rheumatologists per population of 41,658.3 Comparing this finding to the number of hospitalization and ambulatory healthcare visits, the highest number of visits, or need for care, was in the South. Furthermore, the study cited above reported the highest arthritis prevalence in the South.

In addition to regional differences, access to care based on population size is also the norm, as patients in areas with less than 50,000 population often must travel 200 or more miles to see a rheumatologist. The ratio of pediatric rheumatologists is much higher (229,442 children/physician), and it is estimated that only one-quarter of those aged 18 or younger with juvenile arthritis are currently able to see a rheumatologist.3

 

• 1. Barbour KE, Moss S, Croft JB, et al. Geographic variations in arthritis prevalence, health-related characteristics, and management — United States, 2015. MMWR Surveill Summ 2018;67(No. SS-4):1–28. DOI: http://dx.doi.org/10.15585/mmwr.ss6704a1 [314].
• 2. Barbour KE, Helmick CG, Boring M, Brady TJ. Vital signs: prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation — United States, 2013–2015. Morb Mortal Wkly Rep. 2017;66:246–253. DOI: http://dx.doi.org/10.15585/mmwr.mm6609e1 [128].
• 3. a. b. American College of Rheumatology. 2015 Workforce study of rheumatology specialists in the United States. Atlanta, GA. 2015. https://www.rheumatology.org/portals/0/files/ACR-Workforce-Study-2015.pdf [315] Accessed March 26, 2018.

There are many challenges to the management of patients with arthritis that need to be addressed in the future, including, but not limited to, access to specialty care for timely and accurate diagnosis, appropriate use of non-pharmacologic modailities and pharmacotherapy, including targeted small molecule and newer biologic disease modifying anti-rheumatic drugs (DMARDs), adherence to pharmacotherapy, and addressing comorbid medical conditions in patients with various forms of arthritis.

 

Access to Specialty Care

The American College of Rheumatology (ACR) conducted a workforce study in 2015 and noted that the demand for care of patients with arthritis would continue to increase with the aging of the US population.1 Major areas that were identified include the role of primary care providers in the diagnosis and management of common forms of arthritis (eg, osteoarthritis, fibromyalgia, gout) and strategies to improve options for access to rheumatologist specialty care for patients with rheumatoid arthritis, psoriatic arthritis, spondyloarthritides, and systemic autoimmune rheumatic diseases. Training of more mid-level providers (ie, nurse practitioners and physician assistants) and more health professionals (eg, nurses, physical therapists, and occupational therapists) in the care of patients with rheumatic and musculoskeletal diseases would work to address some of this demand.

In addition to issues regarding workforce, there are potential barriers to care including insurance coverage, high co-pays, and limits on number for visits for rehabilitation services such as physical therapy and occupational therapy. Adding to the cost of non-pharmacologic and pharmacologic interventions, especially newer biologic DMARDS, and pharmacy benefit reimbursement plans, are barriers due to high co-pays and prior authorization required for newer pharmacologic interventions.

 

Appropriate Use of Treatment Modalities

Funding of clinical trials to provide best evidence of the efficacy of treatment modalities, including non-pharmacologic interventions is needed. It is extremely important that evidence-based treatments be translated into clinical practice through the use of evidence-based recommendations published by nationally recognized professional societies. Such recommendations exist for the management of most forms of arthritis including, but not limited to, gout, osteoarthritis, rheumatoid arthritis, axial spondyloarthritis (formerly known as ankylosing spondylitis), psoriatic arthritis, and fibromyalgia. These recommendations include the use of both non-pharmacologic and pharmacologic modalities; it is felt to be important to emphasize the role of the former approaches particularly for osteoarthritis and fibromyalgia.

 

Adherence to Treatment Modalities

Virtually all forms of arthritis and systemic autoimmune rheumatic diseases are chronic conditions and effective treatments require patient participation, whether that is taking medications regularly (eg, urate-lowering therapy for gout) or making lifestyle changes such as adhering to dietary changes, a lifelong pattern of physical activity, or using cognitive behavioral therapy or mind-body techniques.

 

Management of Comorbid Medical Conditions

Patients with various forms of arthritis have an increased risk for cardiovascular comorbidities including coronary artery disease. While control of systemic inflammation appears to be important in ameliorating this risk, it is important for practitioners to focus on reducing other factors that contribute to increased cardiovascular disease risk including overweight and obesity, lack of physical activity, smoking, hypertension, hyperlipidemia, and poorly controlled type 2 diabetes mellitus. Depression also has been recognized as contributing to persistent pain, reduced physical function, and impaired quality of life in patients with various forms of arthritis. There is an ongoing need for care coordination between the rheumatology specialist and the primary care provider, particularly in patients who require co-management.

Meeting current and future needs will require a wealth of data currently not available or accessible. In the broad scope of musculoskeletal diseases, data currently either not available or inaccessible to BMUS analysts include treatment cost/benefits, medical workforce, geographic data at detail levels (due to small sample sizes), and outcomes.

In addition, many of the requests for additional data and analysis are beyond the scope of the current BMUS project due to staff size, staff expertise, and funding. 

• 1. American College of Rheumatology. 2015 Workforce study of rheumatology specialists in the United States. Atlanta, GA. 2015. https://www.rheumatology.org/portals/0/files/ACR-Workforce-Study-2015.pdf [315] Accessed March 26, 2018.

Major unmet needs for patients with arthritis include new, effective interventions for the safe treatment of chronic pain, improving insurance coverage for effective evidence-based, non-pharmacologic interventions, as well as newer, targeted small molecules, biologic DMARDs, and the development and approval of Disease Modifying Osteoarthritis Drugs (DMOADs) to slow or prevent progression of osteoarthritis.

Additionally, there is an ongoing need for research funding to understand the pathophysiology of the various forms of arthritis with the goal of estabilishing effective strategies for primary prevention, determining the appropriate timing for surgical intervention and the role of pre- and post-operative exercise programs to maximize functional recovery after surgical interventions, and understanding the underlying reasons for the observed sex/gender and race/ethnicity disparities in most forms of arthritis and systemic autoimmune rheumatic diseases.

Meeting future patient care needs will require increasing the workforce size of medical professionals. The 2015 Workforce Study by the American College of Rheumatology reported an excess demand for adult rheumatology care givers over current workforce projections of nearly 3200 professionals by 2030 and an excess demand of nearly 200 professionals in pediatric rheumatology.1 Other specialists in the care of arthritis likely show similar workforce demands.

• 1. American College of Rheumatology. 2015 Workforce study of rheumatology specialists in the United States. Atlanta, GA. 2015. https://www.rheumatology.org/portals/0/files/ACR-Workforce-Study-2015.pdf [315] Accessed March 26, 2018.

The use of ICD-9-CM codes for clinical and public health purposes ended with the implementation of ICD-10-CM codes effective October 1, 2015. Standard definitions of generic and specific types of arthritis need to be developed for clinical and public health researchers using the new ICD-10-CM codes.

The crosswalk presented HERE [316] is for informational purposes only and should be carefully reviewed before used in future analysis.