Prevalence and risk factors for chloroquine maculopathy and role of plasma chloroquine and desethylchloroquine concentrations in predicting chloroquine maculopathy

Aim To determine the prevalence and to identify the risk factors of chloroquine maculopathy (CM), and to evaluate the association of plasma chloroquine (CQ) and desethylchloroquine (DCQ) levels and CM. Methods Rheumatoid arthritis (RA) patients who had taken CQ for at least 6 months and stable CQ dosage for at least 2 months were included. CM was diagnosed by dilated ocular examination and automated visual field. Plasma CQ and DCQ levels were determined by liquid chromatography tandem mass spectrometry method. Logistic regression was used to explore risk factors associated with CM. Results One hundred and ninety‐three patients were included with median CQ duration (range) of 50.2 months (6.0–269.8) and cumulative dose of 137.4 g (16.4–1226.5). The prevalence of CM was 13.5%. Factors associated with CM identified from univariate analysis were age > 60 years, and creatinine clearance with odds ratio (OR) (95%CI) of 5.79 (2.42, 13.84), and 0.98 (0.96, 1.00). In multivariate analysis, older age, usage > 5 years, and current dose from 2.5 mg/kg ideal body weight [IBW]/day were the factors significantly associated with CM with OR of 5.89 (2.38, 14.57), 2.94 (1.10, 7.83), and 3.32 (1.04, 10.60), respectively, while plasma CQ and DCQ showed no association with CM. Conclusions The prevalence of CM was 13.5% among RA patients taking CQ for at least 6 months. Age > 60 years, duration of CQ usage > 5 years and current CQ dose ≥2.5 mg/kg IBW/day were the risk factors for CM. The plasma CQ or DCQ levels demonstrated no correlation in developing CM.