ABSTRACT
OBJECTIVES: Hydroxychloroquine is widely used to treat certain viral and rheumatic diseases including systemic lupus erythematosus. Cardiac arrhythmia is an important safety issue with hydroxychloroquine. The aim of this study was to investigate whether hydroxychloroquine increases new-onset arrhythmia among patients with systemic lupus erythematosus. METHODS: This was a nested case-control study using data from the Longitudinal Health Insurance Database of Taiwan. A conditional logistic regression model was used to analyse differences in the risk of arrhythmia between systemic lupus erythematosus patients with and without hydroxychloroquine treatment after controlling for related variables. RESULTS: A total of 2499 patients with newly diagnosed systemic lupus erythematosus were identified (81% females), of whom 251 were enrolled in the new-onset arrhythmia group (mean age 50.4 years) and 251 in the non-arrhythmia group (mean age 49.1 years). There was no significantly increased risk of cardiac arrhythmia (adjusted odds ratio = 1.49, 95% confidence interval: 0.98-2.25) or ventricular arrhythmia (adjusted odds ratio = 1.02, 95% confidence interval: 0.19-5.41) between the patients with and without hydroxychloroquine treatment. In addition, there were no significant differences in the risk of arrhythmia between those receiving hydroxychloroquine treatment for <180 days or ≥180 days, with a drug adherence rate of <50% or ≥50%, and receiving a daily dose of <400 mg or ≥400 mg. CONCLUSION: In patients with systemic lupus erythematosus, hydroxychloroquine treatment did not significantly increase the risk of cardiac arrhythmia or life-threatening ventricular arrhythmia regardless of the different hydroxychloroquine treatment duration, drug adherence rate, or daily dose.