Background/Purpose:  Treatment with disease-modifying antirheumatic drugs (DMARDs) is considered the standard of care for rheumatoid arthritis (RA). Over the past two decades, major advances have occurred in the treatment of RA with development of biologic DMARDS including tumor necrosis factor (TNF) inhibitors. It is not well-studied in what sequence these biologic DMARDs are being offered in RA patients in recent years. We aimed to describe patterns of biologic DMARD treatment for RA and identify factors associated with initial and subsequent choice of biologic DMARDs.

Methods: We conducted a prospective cohort study using claims data from a US commercial health plan (2004-2013) and Medicaid (2000-2010). We identified patients who aged ≥18 years with two diagnoses of RA (ICD-9 diagnosis code 714.xx) that are 7-365 days apart, first of which was defined as the index diagnosis. We then identified three separate groups of patients based on their DMARD use in the 365 day period pre-index: 1) incident RA patients who were naïve to any DMARDs, 2) prevalent RA patients with or without non-biologic DMARDs but naïve to biologic DMARDs and 3) prevalent RA patients with prior use of a biologic DMARD. Multivariable logistic regression models examined the effect of patient demographics, clinical characteristics and health care 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 DMARD-naïve incident RA patients and 93,534 biologic-naïve prevalent RA patients and 23,232 biologic-experienced patients (Table 1). Patients in the commercial health plan were 87% more likely to initiate a biologic DMARD than those in Medicaid. African Americans were 30-40% less likely to initiate or switch biologics in all three RA groups when compared to White, non-Hispanic population. Prior use of steroid and non-biologic DMARD had positive association with biologic initiation as well as subsequent switching to another biologic drug. Etanercept (51%), adalimumab (22%), and infliximab (22%) were most commonly used first- and second-line biologics; anakinra and golimumab were most likely to be switched by other biologics (Table 2).

Conclusion:  Younger age, private insurance type, and White race were significantly associated with higher odds of getting initial and subsequent treatment with biologics. There may be a need for future research examining the impact of selective prescribing of biologics on RA-related clinical outcomes.