Escalation to Biologics After Methotrexate Among USVeterans With Rheumatoid Arthritis Grouped by Rural Versus Urban Areas

Racial and ethnic disparities in rheumatoid arthritis (RA) outcomes are well recognized. However, whether disparities in RA treatment selection and outcomes differ by urban versus rural residence, independent of race, have not been studied. Our objective was to evaluate whether biologic disease‐modifying antirheumatic drug (bDMARD) initiation after methotrexate administration differs by rural versus urban residence among veterans with RA. In this retrospective cohort study using national US Veterans Affairs (VA) databases, we identified adult patients with RA based on the presence of diagnostic codes and DMARD administration. We included patients receiving an initial prescription of methotrexate (index date) between 2005 and 2014, with data through 2016 used for follow‐up. Urban–rural status was categorized using the Veteran Health Administration's Urban/Rural classification. Our primary outcome of interest was time to biologic initiation within two years of starting methotrexate. Multivariable Cox proportional hazards models were conducted adjusting for demographics, comorbidities, and rheumatoid factor or anti‐cyclic citrullinated peptide positivity. Among 17,395 veterans with RA (88% male, 42% with rural residence) fulfilling eligibility criteria, 3,259 (19%) initiated a biologic within the first two years of follow‐up. In multivariable models, residence in an urban area was associated with a statistically significant higher biologic administration compared to rural areas (adjusted hazard ratio 1.10 [95% confidence interval 1.02–1.18]). Our study found only modest differences in the initiation of biologic therapies among rural‐ versus urban‐residing veterans with RA in the VA health care system. These findings suggest that disparities are not easily explained by rurality within the VA health care system.