Arthritis is the leading cause of disability in the United States (1), potentially limiting affected persons from walking a few blocks or climbing a flight of stairs. Using Medical Expenditure Panel Survey (MEPS) data, CDC analyzed national and state-specific direct costs (i.e., medical expenditures) and indirect costs (i.e., lost earnings) attributable to arthritis and other rheumatic conditions (AORC) in the United States during 2003. This report describes the results of that analysis, which indicated that, in 2003, the total cost of AORC in the United States was approximately $128 billion ($80.8 billion in direct and $47.0 billion in indirect costs), equivalent to 1.2% of the 2003 U.S. gross domestic product. Total costs attributable to AORC, by state/area, ranged from $225.5 million in the District of Columbia to $12.1 billion in California. Total costs attributable to AORC have increased substantially since 1997 (2), and that increase is expected to continue because of the aging of the population and increases in obesity and physical inactivity. These findings signal the need for broader implementation of effective public health interventions, such as arthritis and chronic disease self-management programs, which can reduce medical expenditures (3) among persons with AORC.
National direct and indirect costs were derived from the household component of the 2003 MEPS (MEPS-HC), an annual household interview survey of medical conditions, medical system expenditures and utilization, and earnings and employment history (4). MEPS is designed to be representative of the U.S. civilian, noninstitutionalized population; each year's MEPS panel is a subsample of the previous year's National Health Interview Survey. The 2003 MEPS did not include a nursing home component; thus, costs among nursing home residents were excluded from the analysis. During the household interview, MEPS respondents described all medical conditions for which they had sought care from a health-care provider. Each of these medical conditions was later assigned an International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) code by medical coders. The 2003 MEPS-HC response rate was 71.9%. AORC cases in MEPS were identified using three-digit ICD-9-CM codes selected by the National Arthritis Data Workgroup* (5). The 2003 MEPS sample consisted of 23,352 participants aged ≥18 years, and 4,801 participants met the case definition for AORC.
Direct per-person costs attributable to AORC were estimated using a series of four-stage regression analyses (6) that modeled the probability and magnitude of medical care expenditures among adults aged ≥18 years. This modeling included adjustment for the following variables: age (18–44, 45–64, or ≥65 years), sex, race (white or nonwhite), ethnicity (Hispanic or non-Hispanic), marital status (single, currently married, widowed, separated, or divorced), highest educational attainment (less than high school, high school graduate, some college, college graduate, or graduate school), health-insurance status (no insurance, public insurance only, or any private insurance), and the presence of nine other high-cost chronic conditions (hypertension, other forms of heart disease, pulmonary disease, stroke, other neurologic conditions, diabetes, cancer, mental illness, or non-AORC musculoskeletal conditions). The average per-person direct cost attributable to AORC was the difference between the observed and corresponding expected medical costs. Expected costs simulated costs among persons with AORC as if they did not have AORC (2). Average per-person direct costs were generated for overall expenditures and for each of the following four cost categories: 1) ambulatory care, 2) emergency department and inpatient services, 3) prescriptions, and 4) other costs (i.e., home health care, vision aids, dental visits, and medical devices). Finally, total national direct costs were calculated as the product of the number of persons aged ≥18 years reporting AORC and the average per-person direct costs.
Indirect per-person costs attributable to AORC were derived from a similar four-stage analysis that modeled the probability of employment and the magnitude of lost earnings among persons aged 18–64 years. However, age was categorized differently (18–34, 35–44, 45–54, and 55–64 years), and no adjustment was made for health-insurance status. Total indirect costs were the product of the number of persons aged 18–64 years with AORC who had ever worked and the average lost earnings per person attributable to AORC. All analyses were conducted using statistical software that adjusted for the clustered sampling design of MEPS. The statistical methods used to derive the national direct and indirect cost estimates are described elsewhere (2).
Direct and indirect costs for each state were estimated by applying the state's proportion of overall doctor-diagnosed arthritis (from the 2003 Behavioral Risk Factor Surveillance System [BRFSS]) to the MEPS-derived national cost estimates. State-specific direct costs were estimated for those aged ≥18 years and lost earnings for the working-age population aged 18–64 years. The 2003 BRFSS response rates ranged from 34.4% to 80.4% among states.
In 2003, total direct costs attributable to AORC were $80.8 billion, with an estimated 46.1 million persons aged ≥18 years reporting AORC, and average per-person direct costs of $1,752 (Table 1). Ambulatory care accounted for the highest per-person direct costs ($914), followed by emergency department and inpatient services ($352), prescriptions ($338), and other costs ($146) (Table 1). Total indirect costs attributable to AORC were $47.0 billion; average per-person lost earnings were $1,590 among 29.5 million working-age adults. National direct and indirect costs totaled $128 billion. Among states/areas, total costs attributable to AORC ranged from $225.5 million in the District of Columbia to $12.1 billion in California; New York and Texas had the next highest total costs at $8.7 billion (Table 2).
National direct costs attributable to AORC increased 24% during 1997–2003, from $64.8 billion (adjusted to 2003 dollars using the medical care component of the Consumer Price Index) to $80.8 billion (2). Despite changes in the treatment of persons with AORC during 1997–2003, including introduction of expensive medications in two drug classes, the coxibs† (e.g., Celebrex™ [Pfizer Pharmaceutical Company; New York, New York]) and biologics (e.g., TNF§ inhibitors), and an increase in the number of knee and hip joint replacements performed, the average per-person direct costs were similar ($1,762 in 1997 [in 2003 dollars] and $1,752 in 2003). The increase in total direct costs resulted from the increase in the number of persons (9 million) with AORC in 2003, attributable to the increase in population (predominantly in the ages 45–64 years cohort) and the increased prevalence of self-reported AORC among adults aged ≥50 years (2).
The findings in this report are subject to at least two limitations. First, direct costs likely were underestimated because MEPS does not capture costs associated with complementary and alternative medicines (persons with arthritis are among the major consumers of these medicines ), long-term mental health services, and nondurable medical goods. Similarly, indirect costs did not capture loss of unpaid work such as homemaking, child care, and volunteer work. Other expenses associated with treatment of illness, such as transportation, accommodation, and lost wages among family members were not measured by MEPS and therefore were not included in this analysis. Second, state-specific direct and indirect cost estimates were simply derived using state-level prevalences and were not adjusted for differences among states in provider charges, treatment resources, or wage differentials. Thus, costs among states with medical expenditures or wages higher than the national mean likely are underestimated, and costs among those below the mean overestimated. Deriving cost estimates from state-level MEPS data was not possible because these data were available for only 30 of the largest states.
The substantially increased costs of AORC in 2003 were driven by an increase in number of persons with AORC. Costs likely will continue rising because the number of persons with arthritis is projected to continue to increase, with another 8 million arthritis cases anticipated during 2005–2015 (8). Without cost-reduction strategies, the economic burden of AORC will continue to increase. This trend underscores the need for wide-scale implementation of interventions that reduce medical expenditures and lost earnings among persons with AORC. Self-management programs such as the Arthritis Self-Help Program are cost-effective strategies to reduce direct costs associated with arthritis (3). Self-management programs foster skills in coordinating work accommodations and pain management (through physical activity and weight management) and are essential for reducing the economic and societal burden of AORC.