Rheumatoid arthritis medication adherence in a health system specialty pharmacy.

Abstract

To assess adherence to specialty medications for rheumatoid arthritis (RA) at an integrated health system specialty pharmacy (HSSP) and identify characteristics associated with adherence. Single-center, retrospective cohort study. Study patients were adults with RA who filled at least 3 prescriptions for biologic disease-modifying antirheumatic drugs (bDMARDs) between July 1, 2016, and June 30, 2017, at an integrated HSSP. Data were collected from pharmacy claims and electronic health records. The primary outcome, adherence, was measured using proportion of days covered (PDC). Proportional odds logistic regression was used to test association between PDC and age, gender, race, insurance type, and out-of-pocket costs. We included 675 patients: 77% were female, 90% were White, 29% were naive to treatment at initial dispensing, 60% held commercial insurance, and the median age was 56 years. Median (interquartile range [IQR]) patient out-of-pocket cost per fill was $1.50 ($0-$5). Median (IQR) PDC was 0.95 (0.84-1.00); 80% of patients achieved PDC of 0.80 or higher. Higher adherence was more likely in patients who were male (odds ratio [OR], 1.58; 95% CI, 1.15-2.18; P = .005], naive to specialty medication treatment (OR, 3.04; 95% CI, 2.21-4.18; P < .001), and older in age (per 10 years: OR, 1.17; 95% CI, 1.04-1.32; P = .008), and adherence had a significant nonlinear association with average cost per fill (P = .006); associations with race and insurance type were not significant. At an integrated HSSP, patients with RA paid low out-of-pocket costs for bDMARD therapy and achieved high treatment adherence. Data suggest that integrated HSSPs assist patients in removing financial barriers to treatment.