Risk of Hospitalized Infection and Initiation of Abatacept versus TNF Inhibitors among Patients with Rheumatoid Arthritis: a Propensity Score-Matched Cohort Study.

OBJECTIVE: We aimed to evaluate the comparative risk of hospitalized infection among patients with rheumatoid arthritis (RA) who initiated abatacept versus a TNF inhibitor (TNFi).

METHODS: We identified RA patients aged >18 years with >2 RA diagnoses who initiated abatacept or a TNFi using claims data from Truven MarketScan database (2006-2015). The primary outcome was a composite endpoint of any hospitalized infection. Secondary outcomes were bacterial infection, herpes zoster, and infections affecting different organ systems. We performed 1:1 propensity score (PS) matching between the groups to control for baseline confounders. We estimated incidence rates (IR) and hazard ratio (HR) with 95% confidence intervals (CI) for hospitalized infection.

RESULTS: We identified 11,248 PS-matched pairs of abatacept and TNFi initiators with median age of 56 years, and 83% female sex. The IR per 1,000 person-years for any hospitalized infection was 37 among abatacept initiators and 47 in TNFi initiators. The HR for the risk of any hospitalized infection associated with abatacept versus TNFi was 0.78 (95% CI 0.64-0.95) and remained lower when compared to infliximab (HR 0.63, 95% CI 0.47-0.85), while no significant difference was seen compared with adalimumab and etanercept. The risk of secondary outcomes was lower for abatacept for pulmonary infections, and similar to TNFi for the remaining outcomes.

CONCLUSIONS: In this large cohort of RA patients who used abatacept or TNFi as a first or second-line biologic agent, we found a lower risk of hospitalized infection after initiating abatacept versus TNFi which was driven mostly by infliximab. This article is protected by copyright. All rights reserved.