Hydroxychloroquine and the risk of respiratory infections among RA patients.

Objectives To determine the effect of hydroxychloroquine on the incidence of new respiratory infections in a large registry of rheumatoid arthritis (RA) patients compared with a matched cohort receiving other conventional disease-modifying antirheumatic drugs (csDMARDs). Methods We reviewed physician-reported infections including upper respiratory infections (URI), bronchitis and pneumonia in the Corrona RA registry from June 2008 to February 2020 with the goal of comparing infections in biologic/targeted synthetic (b/ts) DMARDs naive HCQ starts compared with starts of other csDMARDs and no HCQ. Patients on different interventions were compared using time-varying adjusted Cox models adjusting for age, sex, duration of RA, BMI, disease activity, smoking status, concurrent medications, season of the year, year of onset and history of serious infections, diabetes or cardiovascular disease (CVD). A secondary analysis in a set of propensity-matched starts were also compared adjusting for time-varying covariates. The analysis was repeated including URI and bronchitis only and also for serious respiratory infections only. Results No evidence of differences was found in the incidence of any respiratory infection (URI, bronchitis, pneumonia) in patients receiving HCQ compared with other csDMARDs: HR=0.87 (0.70 to1.07) in adjusted analyses and HR=0.90 (0.70 to 1.17) in adjusted matched analysis. Similar results were found in the analysis of URI and bronchitis only and for serious respiratory infections only. Conclusions In patients with RA, the risk for respiratory infections was similar among patients using HCQ as compared to other non-biologic DMARDs.