Abstract
OBJECTIVE: To describe the pattern and risk factors for antimalarial (AM)-induced retinopathy in patients with rheumatic diseases. METHODS: A retrospective chart review was conducted at an urban Canadian center for patients with AM use of more than 3 months and documented retinopathy screening. Univariate and multivariate regression analyses were performed to determine risk factors for retinopathy. Sensitivity analyses included stratification of analysis by method of screening and by hydroxychloroquine (HCQ) versus chloroquine (CQ). RESULTS: A total of 613 patients were included in the final analysis, with systemic lupus erythematosus (SLE) (n = 259) as the most common diagnosis. Definite AM-induced retinal toxicity was observed in 12 patients, 11 of whom had SLE. The earliest diagnosis of toxicity occurred after 5.4 years of AM therapy, and the prevalence beyond 5 years was 3.1%. In univariate analysis, a diagnosis of SLE (P = 0.009; odds ratio [OR]: 15.66; 95% confidence interval [CI]: 2.01-122.05), the daily weight-based dose of HCQ (P = 0.044; OR: 1.49; 95% CI: 1.01-2.20), cumulative CQ dose (P = 0.014; OR: 4.80; CI: 1.37-16.84), and daily CQ weight-based dose (P = 0.0001; OR: 5.70; 95% CI: 2.41-13.49) were significantly associated with toxicity. In multivariate analysis, diagnosis of SLE (P = 0.022; OR: 12.14; 95% CI: 1.44-102.44) and daily CQ weight-based dose (P = 0.005; OR: 1.83; 95% CI: 1.83-26.75) were significant after adjusting for standard covariates. CONCLUSION: The risk of AM-induced retinopathy increases after 5 years of therapy. There may be higher rates of toxicity in patients with SLE because of longer duration of treatment, higher weight-based dosages, and more CQ use in this population, and SLE may be an independent risk factor.