Factors associated with drug survival on first biologic therapy in patients with rheumatoid arthritis: a population-based cohort study

Lack of sufficient head-to-head trials comparing biologic disease-modifying antirheumatic drugs (bDMARDs) in rheumatoid arthritis (RA), makes the choice of the first bDMARD a matter of rheumatologist's preference. Longer drug survival on the first bDMARD usually correlates with early remission. We aimed to identify factors associated with longer drug survival. We conducted a population-based retrospective longitudinal cohort study. We identified RA patients using the relevant International Classification of Disease 9th codes. "True" RA patients were defined as patients fulfilling, additionally, at least one of the following: receiving conventional DMARDs (cDMARDs), being positive for rheumatoid factor or anti-cyclic citrullinated peptide, or being diagnosed by a rheumatologist. We compared drug survival times and identified factors associated with longer drug survival. We identified 4268 true RA patients between the years of 2000-2017. 820 patients (19.2%) received at least one bDMARD. The most commonly prescribed bDMARDs were etanercept (352, 42.9%), adalimumab (143, 17.4%), infliximab (142, 17.3%) and tocilizumab (58, 7.1%). Infliximab was associated with the longest drug survival (47.1 months ± 46.3) while golimumab was associated with the shortest drug survival (14.9 months ± 15.1). Male gender [hazard ratio (HR) = 0.76, 95% confidence interval (CI), 0.63-0.86, p = 0.001], concurrent conventional DMARDs use (HR = 0.79, 95% CI 0.68 - 0.98, p = .031) and initiating bDMARD therapy in earlier calendric years (HR = 1.12, 95% CI 1.10 -1.18, p = 0.0001) were associated with longer drug survival. Male gender, concomitant cDMARDs and initiating biologic therapy at earlier calendric years are associated with longer drug survival.