To study the relationship between hydroxychloroquine (HCQ) use and new-onset atrial fibrillation in patients with systemic lupus erythematosus (SLE).
A retrospective cohort of adult patients with SLE was constructed from December 1, 2014 to May 30, 2017. Patients were categorized as either HCQ users or nonusers. The primary outcome was incident atrial fibrillation. Secondary outcomes included incident ventricular arrhythmias (composite of ventricular tachycardia, ventricular fibrillation, or torsades de pointes). Outcomes were adjudicated by review of the electronic health record. Statistical analyses included simple and multivariable logistic regression tests to estimate the association between HCQ use and incident atrial fibrillation after adjusting for relevant confounders. Propensity score matching analysis was completed.
Our study included 1,647 patients with SLE, of which 917 were HCQ users and 730 were nonusers. A total of 23 atrial fibrillation events occurred, including 3 in HCQ users and 20 in nonusers. Logistic regression analysis showed an odds ratio (OR) of 0.12 (95% confidence interval [95% CI] 0.034-0.39, P = 0.0005) for incident atrial fibrillation and 2.39 (95% CI 0.25-23.0, P = 0.45) for ventricular arrhythmias. Results remained significant in the fully adjusted and propensity score-matched models.
In this exploratory study, HCQ use was associated with an 88% decrease in the risk of incident atrial fibrillation in patients with SLE. Considering the increased cardiovascular risk in SLE, incorporation of HCQ into the regimen may be beneficial for both disease manifestations and reducing the risk of atrial fibrillation. Further studies would be needed to confirm the antifibrillatory benefit of this relatively safe and low-cost medication.