A cohort study of more than 3,000 persons who received hydroxychloroquine for 5 or more years with guideline-recommended serial retinopathy screening found that the overall risk for incident retinopathy was low, with most documented cases being mild. Higher hydroxychloroquine dose was associated with progressively greater risk. The findings are published in Annals of Internal Medicine.

Hydroxychloroquine is recommended for patients with systemic lupus erythematosus and some other inflammatory conditions, but vision-threatening retinopathy is a serious long-term adverse effect. Guidelines recommend keeping dosing at 5 mg/kg of body weight per day or lower. However, available study evidence supporting this is relatively weak.

Researchers from Kaiser Permanente Northern California and Harvard Medical School studied 3,325 persons who received hydroxychloroquine for 5 or more years between 2004 and 2020 to characterize the long-term risk for incident hydroxychloroquine retinopathy and examine the degree to which average hydroxychloroquine dose within the first 5 years of treatment predicts this risk.

The researchers used pharmacy and health records to analyze hydroxychloroquine dosing and reviewed annual optical scans over time to determine if there was evidence of retinopathy. If retinopathy cases were identified, they were classified as mild, moderate, or severe. The researchers then estimated the risk for developing retinopathy after 15 years according to average dosing levels during the first 5 years.

They found that 81 participants developed hydroxychloroquine retinopathy with overall cumulative incidences of 2.5 and 8.6 percent occurring after 10 and 15 years, respectively, with the risk being greater for those given a higher dose during the first 5 years of treatment. The researchers note that regular screening can identify this issue at an early and treatable stage.