Redwood City, CA—All patients with systemic lupus erythematosus—and sometimes those with other inflammatory conditions—are recommended to take hydroxychloroquine. The problem is that a critical long-term adverse effect is vision-threatening retinopathy.

A new study published in Annals of Internal Medicine sought to calculate the long-term risk for incident hydroxychloroquine retinopathy. It also examined how much average hydroxychloroquine dose within the first 5 years of treatment predicts the risk.

The cohort study led by researchers from Kaiser Permanente Northern California used the integrated health network, selecting all adult patients who received hydroxychloroquine for 5 or more years between 2004 and 2020 and had guideline-recommended serial retinopathy screening.

The study team assessed hydroxychloroquine dosing from pharmacy dispensing records, while determining incident hydroxychloroquine retinopathy by central adjudication of spectral domain optical coherence tomography with severity assessment (i.e., mild, moderate, or severe). Risk for hydroxychloroquine retinopathy also was estimated over 15 years of use based on hydroxychloroquine weight-based dose (≤5 mg/kg, 5-6 mg/kg, or >6 mg/kg per day).

The results indicated that among 3,325 patients in the primary study population, 81 developed hydroxychloroquine retinopathy (56 mild, 17 moderate, and 8 severe) with overall cumulative incidences of 2.5% and 8.6% at 10 years and 15 years, respectively.

The researchers advised that the cumulative incidences of retinopathy at 15 years were 21.6% for higher than 6 mg/kg per day, 11.4% for 5 mg/kg to 6 mg/kg per day, and 2.7% for 5 mg/kg per day or lower. They added that the corresponding risks for moderate to severe retinopathy at 15 years were 5.9%, 2.4%, and 1.1%, respectively.

The study’s limitation included possible misclassifications of dose due to filled-prescription nonadherence.

“In this large, contemporary cohort with active surveillance retinopathy screening, the overall risk for hydroxychloroquine retinopathy was 8.6% after 15 years, and most cases were mild,” the authors concluded. “Higher hydroxychloroquine dose was associated with progressively greater risk for incident retinopathy.”

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