Hydroxychloroquine Use and Cardiovascular Events Among Patients With Systemic Lupus Erythematosus and Rheumatoid Arthritis

Objective. We evaluated the potential temporal association between hydroxychloroquine (HCQ) use and cardiovascular (CV) events among patients with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA).Methods. We conducted a nested case-control study within inception cohorts of SLE and RA patients using administrative health databases including the entire population of British Columbia, Canada. We identified cases with incident CV events, including myocardial infarction (MI), stroke, or venous thromboembolism (VTE). We matched each case with up to 3 controls on age, sex, and rheumatic disease. HCQ exposure was categorized by the time between the last HCQ prescription date covered and the index date as current use, recent use, remote use, or never used. We used conditional logistic regression to assess the association between HCQ exposure and CV events, using remote use as the reference group.Results. We identified 10,268 cases and 29,969 controls. Adjusted conditional odd ratios (cORs) and 95% confidence intervals (95% CIs) for current HCQ use relative to remote use were 0.86 (0.77-0.97) for combined CV events, 0.88 (0.74-1.05) for MI, 0.87 (0.74-1.03) for stroke, and 0.74 (0.59-0.94) for VTE. Recent HCQ users and nonusers had similar odds of combined CV events as remote users (cORs 0.93, 95% CI 0.77-1.13 and 0.96, 95% CI 0.88-1.04, respectively).Conclusion. In this nested case-control study of patients with SLE and RA, we found a reduced risk of overall CV events associated with current HCQ use, including reductions in VTE and trends toward reductions in MI and stroke. These findings suggest a possible cardiovascular preventative benefit of HCQ use.