Studies by Melles and Marmor helped quantify the risk of retinopathy and influenced guidelines for dosing put out by many societies. For daily consumption of 4.0 to 5.0 mg/kg, the prevalence of retinal toxicity remained less than 2% within the first 10 years of use but was found to rise to almost 20% after 20 years of use. The American Academy of Ophthalmology proposed that dosing of 5 mg per kg or less are considered reasonable doses and eye examinations for those at low risk can be done at baseline and then annually starting at year 5.
Melles et al 2023
Melles and colleagues again set out to characterize the long-term risk for incident hydroxychloroquine retinopathy.
The author studied all patients aged 18 years or older who received hydroxychloroquine for 5 or more years between 2004 and 2020 and had guideline-recommended serial retinopathy screening. Patients included in the study had a range of rheumatologic diagnoses including rheumatoid arthritis, other chronic inflammatory arthritis, SLE, Sjögren syndrome, other systemic connective tissue diseases, cutaneous lupus, or other dermatologic conditions. Overall, the most common indications for hydroxychloroquine in this study were rheumatoid arthritis and SLE.
There were 3325 patients included in the study. 620 (18.6%) used more than 6 mg/kg hydroxychloroquine. 532 (16.0%) used 5 to 6 mg/kg and 2173 (65.4%) used 5 mg/kg or less
Risk of Retinopathy at 10 and 15 years
The risk of retinopathy at 10 and 15 years using various doses of HCQ is shown below:
