Retinal Complications in Systemic Lupus Erythematosus Patients Treated with Antimalarial Drugs

Objective Hydroxychloroquine (HCQ) and chloroquine (CQ) are key drugs in systemic lupus (SLE) and related diseases. Retinal toxicity remains the most concerning complication. We studied factors potentially associated with retinal toxicity, using case-control analyses. Methods Within our lupus clinic cohort, we identified patients with retinal changes using the SLICC Damage Index. We confirmed HCQ/CQ retinopathy with chart review, and selected up to three SLE controls for each case, matched on age at SLE diagnosis and SLE duration. Results Over an average 12.8 years of follow-up, within 326 patients exposed to antimalarial drugs, 18(5.5%) developed retinal toxicity. The minimum number of years of HCQ/CQ exposure before retinopathy developed was 8 years (maximum 33 years). Mean HCQ/CQ duration was similar in cases (18.5 years, 95% CI 15.2, 21.7) and controls (16.7 years, 95% CI 14.3, 19.0) likely due to our matching on SLE duration. Versus controls, cases tended to have more renal disease (cases 22.2%, controls 14.8%) and were slightly less likely to be Caucasian (cases 61.1%, controls 74.1%), but neither variables reached statistical significance. Among patients with retinal toxicity, the number previously exposed to CQ was more than three times that in controls. Conclusion Just over 5% of patients developed anti-malarial retinal complications, over an average of 12.8 years. No cases were detected in the first 5 years of therapy. Past CQ use was more common in cases versus controls. Future studies using larger cohorts are underway to better define the roles of therapy duration, race/ethnicity, and other factors.