ObjectiveTo determine the impact of emerging safety data on practice patterns by describing the characteristics of patients initiating and discontinuing advanced therapies for rheumatoid arthritis (RA) before and after January 2021.MethodsThis cohort study evaluated U.S. Veterans with RA between April 2019 and September 2022. This period was divided into two 664‐day periods before and after January 2021. Eligible patients had ≥1 diagnosis code for RA and initiated a tumor necrosis factor inhibitor (TNFi), non‐TNFi biologic, or Janus kinase inhibitor (JAKi). We tested for interaction within regression models to determine whether changes in patient characteristics for tofacitinib users were different from changes observed for other therapies. We also evaluated factors associated with therapy discontinuation in Cox models adjusted for age, sex, and duration on therapy, including assessment for effect modification.ResultsWhen comparing patients with RA initiating tofacitinib before (N=2111) and after (N=1664) January 2021, there was a decrease in mean age (64.1 vs 63.0) and in the proportion with cardiovascular comorbidities (all p<0.01). These changes were significantly different from those observed for patients initiating TNFi or non‐TNFi biologics. Among active advanced therapy users, the likelihood of discontinuation was higher for tofacitinib than TNFi (HR: 1.18 [1.10,1.26], p<0.001). The higher rate of tofacitinib discontinuation was more pronounced in the presence of cardiovascular comorbidities (p<0.05).ConclusionRecent safety data significantly affected prescribing practices for advanced therapies, with a reduction in JAKi initiation and an increase in JAKi discontinuation among older patients and those at high cardiovascular risk.This article is protected by copyright. All rights reserved.image