Incremental Costs of Rheumatoid Arthritis Treatment: A National Population-Based Study 2002-2013

Motivation: Rheumatoid Arthritis (RA) is an autoimmune disease characterized by progressive joint damage leading to pain, aesthetic deformities, and impaired function. Today, over 1.3 million individuals in the U.S. suffer from RA, which disproportionately affects working-age adults. Although RA is not curable, recent advances in medical treatment, such as the introduction of disease-modifying antirheumatic drugs  (DMARDs), can significantly slow disease progression, and have rapidly become the standard of care for newly diagnosed patients.

Objective: Pharmaceutical advancements for RA have revolutionized clinical treatment. However, their downstream effects on healthcare utilization and expenditures are unknown. Compared with surgical intervention and traditional regimens, current medications to curb inflammation and joint destruction are expensive. In this context, we sought to examine recent trends in incremental healthcare utilization and expenditures among RA patients.

Data: We used the pooled cross-sectional 2002-2013 Medical Expenditure Panel Survey (MEPS) and examined nationally representative data from 300,806 individuals ages 18 and older. To identify individuals diagnosed with RA, we used the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 714 or clinical classification code 202, reported in the MEPS medical condition files.

Study Design: We measured RA incremental healthcare utilization across four domains: (1) provider office visits, (2) prescription medications, (3) outpatient procedure visits, and (4) inpatient procedure/hospitalization visits. Additionally, we calculated RA incremental healthcare costs for each of these four categories and total healthcare costs. All dollar values were inflated, using the 2013 all-items Consumer Price Index. We used generalized linear regression (GLM) models to estimate the RA incremental healthcare utilization and costs.

Principal Findings: The average adjusted predictive incremental cost of RA treatment between 2002 and 2013 was $2,433 (95% CI: 2,399-2,467), with prescription drugs accounting for almost half the total cost ($1,252; 95% CI: 1,233-1,271). Between 2002 and 2013, the total predictive incremental healthcare cost of RA treatment increased by 26%, of which 70% was attributed to increased use and cost of prescription drugs (p < 0.001). In particular, the use of biologic DMARDs among RA patients increased from less than 1% in 2002 to 3% in 2013. Biologic DMARDs are expensive. For example, the average total cost of biologic DMARDs in 2013 was $20,833. Additionally, use of other prescription drugs among RA patients increased by 15% (from 9.2 to 10.6 annual 30-day prescription drugs; p < 0.001). In contrast, use of inpatient and outpatient health services declined by 1% (p < 0.050).

Policy Implications and Conclusions: RA is an expensive chronic condition affecting about 1.5% of the U.S. population. In the wake of the Affordable Care Act (ACA) and the national quest to control healthcare costs, the rising cost of RA treatment is concerning. Despite a continuous decline in incremental outpatient and inpatient RA procedures during the last decade, the marginal cost of RA treatment has continued to grow. The increase in prescription drug cost has now surpassed the decline in costs in other areas of healthcare. Accelerating healthcare costs have prompted concern regarding the distribution and availability of expensive, yet effective, treatments.