Background: Biologic disease-modifying antirheumatic drugs (DMARDs) are increasingly used for rheumatoid arthritis (RA) treatment. However, little is known based on contemporary data about the factors associated with DMARDs and patterns of use of biologic DMARDs for initial and subsequent RA treatment.
Methods: We conducted an observational cohort study using claims data from a commercial health plan (2004-2013) and Medicaid (2000-2010) in three study groups: patients with early untreated RA who were naïve to any type of DMARD and patients with prevalent RA with or without prior exposure to one biologic DMARD. Multivariable logistic regression models were used to examine the effect of patient demographics, clinical characteristics and healthcare utilization factors on the initial and subsequent choice of biologic DMARDs for RA.
Results: We identified a total of 195,433 RA patients including 78,667 (40%) with early untreated RA and 93,534 (48%) and 23,232 (12%) with prevalent RA, without or with prior biologic DMARD treatment, respectively. Patients in the commercial insurance were 87% more likely to initiate a biologic DMARD versus patients in Medicaid (OR = 1.87, 95% CI = 1.70-2.05). In Medicaid, African-Americans had lower odds of initiating (OR = 0.59, 95% CI = 0.51-0.68 in early untreated RA; OR = 0.71, 95% CI = 0.61-0.74 in prevalent RA) and switching (OR = 0.71, 95% CI = 0.55-0.90) biologic DMARDs than non-Hispanic whites. Prior use of steroid and non-biologic DMARDs predicted both biologic DMARD initiation and subsequent switching. Etanercept, adalimumab, and infliximab were the most commonly used first-line and second-line biologic DMARDS; patients on anakinra and golimumab were most likely to be switched to other biologic DMARDS.
Conclusions: Insurance type, race, and previous use of steroids and non-biologic DMARDs were strongly associated with initial or subsequent treatment with biologic DMARDs.
Keywords: Antirheumatic agents; Biologic therapy; Rheumatoid arthritis.