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Background and Objective: Chloroquine(CQ) and hydroxychloroquine(HCQ) retinopathy are one of the most morbid complications from long term use of CQ and HCQ which are widely prescribed to rheumatologic patients. Since most of studies and recommendations we rely on nowadays are performed in Caucasian population, the application of these studies and recommendations to Asian population is still doubtful. This study was purposed to determine the prevalence and risk factors of CQ and HCQ retinopathy in Thai rheumatologic patients.
Methods: A retrospective cross sectional study was done on rheumatologic patients receiving either CQ or HCQ from 2004 to 2014. Patients’ data comprising age, sex, body weight, rheumatologic diseases, underlying diseases, daily dose and cumulative dose of CQ or HCQ were reviewed. CQ and HCQ retinopathy were diagnosed by indirect ophthalmoloscopy, Humphrey visual field analyzer or optical coherence tomography.
Results:Two hundred and twenty-six patients were studied. CQ retinopathy was developed in 14 of 165 patients (8.48%) who received CQ with duration ranging from 139 to 2099 days (median 724 days), cumulative dose from 14 to 325 g (median 107 g) and daily dose from 0.3 to 5 mg/kg/day (median 1.9 mg/kg/day). Their age ranged from 27 to 65 years (median 51.5 years). Comparing to non-CQ retinopathy group, only age, sex and body weight showed statistically significant difference. HCQ retinopathy was developed in 2 of 61 patients (3.28%) who received HCQ with duration from 660 to 828 days (median 744 days), cumulative dose from 80 to 130 g (median 105.1 g) and daily dose from 1.9 to 4.4 mg/kg/day (median 3.2 mg/kg/day). Their ages were 36 and 39 years (median 37.5 years). Comparing to non-HCQ retinopathy group, there was no statistically significant difference in studied risk factors.
Conclusions: Most patients develop CQ and HCQ retinopathy earlier than 5 years, younger than 60 years, less cumulative dose and daily dose than those proposed by the revised recommendation on screening for CQ and HCQ retinopathy. Therefore, we recommend screening examination once or twice a year after baseline examination.