Sociodemographic Determinants of Out-of-Pocket Expenditures for Patients Using Prescription Drugs for Rheumatoid Arthritis

Abstract

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease that has a substantial economic impact on patients. Patients with RA are at an increased risk for disability and for loss of income. The inclusion of biologic drugs in RA therapy has increased the cost of treatment. Little is known about the relationship between sociodemographic characteristics and the out-of-pocket (OOP) expenditures for prescription drugs for patients with RA, including biologics, disease-modifying antirheumatic drugs (DMARDs), nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and analgesics.

Objectives: To explore the relationship between sociodemographic characteristics, personal characteristics, and OOP expenditures associated with RA prescription medications. A secondary objective was to measure the average OOP expenditures for different therapeutic classes of RA medications, including biologics, DMARDs, NSAIDs, corticosteroids, and analgesics.

Methods: In this retrospective analysis of Medical Expenditure Panel Survey (MEPS) data from 2009 to 2012, we identified a patient sample of 1090 adults with RA, which represented approximately 9.71 million patients in the MEPS database. The total OOP expenditure was calculated based on the OOP expenditure for each prescription drug corresponding to an individual. Patient variables included age, race, sex, insurance status, number of comorbid conditions, region, area of living, annual family income, and marital status. Logistic regression and generalized linear models were used for analysis. The mean OOP expenditure for therapeutic classes was estimated using nonparametric percentiles from 1000 cluster bootstrap estimates.

Results: Overall, the mean annual OOP expenditure was $273.99 (95% confidence interval [CI], $197.07-$364.75). The OOP expenditures were lower for privately insured (0.31; 95% CI, 0.21-0.45) patients and publicly insured (0.18; 95% CI, 0.12-0.27) patients versus uninsured patients, and for poor (0.60; 95% CI, 0.43-0.84) and low-income (0.69; 95% CI, 0.49-0.97) patients versus high-income patients. The mean annual OOP expenditure decreased with age (0.98; 95% CI, 0.97-0.99), was lower (0.73; 95% CI, 0.58-0.92) for male patients than for female patients, and increased with the presence of comorbidities (1.16; 95% CI, 1.07-1.25). The average annual OOP expenditure was highest for biologics ($2556.73), followed by DMARDs ($89.37). The average annual OOP expenditures were $27.97, $52.36, and $72.51 for corticosteroids, NSAIDs, and narcotic analgesics, respectively.

Conclusions: Age, sex, race, income level, insurance status, and comorbidity status significantly affected patient OOP expenditure. Higher OOP expenditures among the uninsured, female patients, patients with low income levels, and patients with several comorbidities could adversely affect RA therapy. The use of expensive biologics needs to be monitored to reduce prescription-related cost-sharing among patients with RA.

Keywords: Medical Expenditure Panel Survey; analgesics; biologics; comorbidities; corticosteroids; disease-modifying antirheumatic drugs; generalized linear model; income level; insurance status; nonsteroidal anti-inflammatory drugs; out-of-pocket expenditures; prescription drugs; rheumatoid arthritis; sociodemographics; uninsured patients.