Predictors of Medication Adherence in Patients with Rheumatoid Arthritis.

Medication adherence is a significant problem in patients with rheumatoid arthritis (RA), a prevalent autoimmune disease. Due to the equivocal results reported in the research, consistent predictors of medication adherence in patients with RA are undetermined. A cross-sectional descriptive, predictive study of 108 patients with RA was used to: 1) describe self-reported medication adherence to disease modifying anti-rheumatic drugs (DMARDs); 2) compare demographic (age, residence, marital status, employment status, years of education, and ethnicity) and clinical (duration of disease and number of medications) factors of adherent and non-adherent individuals; and 3) determine the predictive power of demographic and clinical factors for DMARD adherence using various cut-points (research-based, mean, and median) on a validated, self-report scale measuring medication adherence. Independent samples t-tests, Chi square analyses, and logistic regression modeling were used to analyze these data. Approximately 90% of the individuals with RA reported adherence with their prescribed DMARD prescriptions. The only demographic and clinical difference between the adherent and non-adherent group was ethnicity (p=0.04); nonwhite individuals reported significantly less adherence with their prescribed DMARDs when compared to white individuals. Logistic regression models identified ethnicity (OR= 3.34-10.1; p< 0.05) and the number of medications taken (OR=1.7; p< 0.05) as predictors of medication non-adherence. These data provide evidence that ethnicity and taking an increased number of prescribed medications are independent predictors of medication adherence in patients with RA. These findings confirm the presence of a health disparity and an area where further research is needed to optimize patient outcomes.