Chloroquine and hydroxychloroquine retinopathy in a cohort with rheumatic diseases in Mexico: prevalence, risk factors, and retinopathy patterns

INTRODUCTION/OBJECTIVES: To compare chloroquine (CQ) and hydroxychloroquine (HCQ) retinopathy prevalence, risk factors, severity, and patterns in a cohort of Hispanic patients with rheumatic diseases in Mexico. METHODS: Retrospective, cross-sectional study of patients with rheumatic diseases treated with CQ/HCQ who underwent retinopathy screening (from 2014 to 2019) with macular spectral domain optical coherence tomography and automated visual field tests. The most recent screening report was included to define the presence or absence of retinopathy. RESULTS: A total of 571 patients were recruited; 27 were excluded due to missing reports. A total of 544 patients were analyzed, 26% (140/544) used CQ, and 74% (404/544) HCQ. Mean age at treatment initiation was 44.9 ± 15.8 years; 95% were female. Retinopathy prevalence was higher with CQ (19%) than HCQ (2%) (P < 0.001). This was consistent in those using antimalarials < 5 years (CQ: 8.5% vs. HCQ: 1.8%; P < 0.007) and those using antimalarials ≥ 5 years (CQ: 33% vs. HCQ: 2.4%; P < 0.001). CQ patients had more years of use at retinopathy diagnosis than HCQ patients (9.0 ± 4.3 vs. 5.1 ± 3.3, P < 0.023). Parafoveal retinopathy pattern was most frequent in patients using CQ (81%) and HCQ (100%), with no isolated perifoveal pattern. Most patients with retinopathy (59%) had a severe grade. In multivariable regression model, CQ was associated with higher odds of retinopathy compared with HCQ (OR, 12.03; 95% CI 4.41-35.74; P < 0.001). Observed independent risk factors for retinopathy were older age at treatment initiation (OR, 1.04; 95% CI 1.00-1.08; P = 0.029) and years of antimalarial use (OR, 1.18; 95% CI 1.09-1.28; P < 0.001). CONCLUSION: CQ poses a higher risk of antimalarial retinopathy than HCQ. Older age at treatment initiation and duration of use were independent risk factors. Parafoveal was the most frequent retinopathy pattern. Key Points • Antimalarial retinopathy prevalence is significantly higher with chloroquine (19%) than with hydroxychloroquine (2%). • Chloroquine use is associated with significantly higher odds of retinopathy compared with hydroxychloroquine (OR, 12.03; 95% CI 4.41-35.74; P < 0.001). • An older age at treatment initiation (OR, 1.04; 95% CI 1.00-1.08; P = 0.029) and years of antimalarial use (OR, 1.18; 95% CI 1.09-1.28; P < 0.001) are independent risk factors for chloroquine/hydroxychloroquine retinopathy. • The most frequently observed antimalarial retinopathy pattern in this cohort of rheumatic patients in Mexico was the parafoveal (85%), with no cases of perifoveal pattern.