To evaluate adherence to newly initiated biologic disease-modifying antirheumatic drugs (bDMARDs) in effectively treated patients with rheumatoid arthritis (RA).
Retrospective cohort study of administrative claims data (IMS PharMetrics Plus) for services incurred from July 1, 2008, to December 31, 2014.
Data from patients with RA aged 18 to 64 years with continuous enrollment for at least 30 months and initiating abatacept, adalimumab, certolizumab pegol, etanercept, golimumab, or infliximab were analyzed. Treatment effectiveness was determined using a validated algorithm. Outcomes included adherence rates (proportion of days covered ≥80%) for 1 year and 2 years, year 2 adherence among patients effectively and noneffectively treated in year 1, year 2 adherence predictors, and year 2 costs and cost predictors.
Across 10,374 patients, adherence rates were 46% for year 1 and 34% for 2 years; rates were lowest for golimumab and highest for infliximab. In year 1, 3076 (29.7%) patients were considered effectively treated. Year 2 adherence was 59% in effectively treated patients, 32% in patients who failed any effectiveness criteria, and 12% in patients who failed only the adherence criterion. Intravenous bDMARDs, older age, male sex, Northeast region, commercial payer, prior DMARD use, index year 2010 or later, and lower preindex all-cause costs each predicted better adherence. Adjusted year 2 all-cause and RA-related costs were $39,425 and $22,123, respectively, for effectively treated patients and $25,313 and $9250 for noneffectively treated patients. Cost predictors included effective treatment, region, payer, and index year.
Adherence to the first bDMARD was suboptimal even in effectively treated patients, suggesting opportunities to improve adherence in patients with RA initiating biologics.