The Prevalence of Hydroxychloroquine Retinopathy and Toxic Dosing, and the Role of the Ophthalmologist in Reducing Both

Abstract

The prevalence of hydroxychloroquine retinopathy (HCR) is important to know because it provides the justification for screening the estimated 350 000 Americans who take the drug. No methodologically sound epidemiologic study of the issue has been done, but many estimates of prevalence have been made, and in the last 20 years their size has increased dramatically. From 1983 to 2003, the estimates were 0%–0.5% for patients taking ≤6.5 mg/kg of actual body weight/day for less than 6 years, and very low for longer durations of use. 1 Mackenzie A.H. Dose refinements in long-term therapy of rheumatoid arthritis with antimalarials. Am J Med. 1983; 75: 40-45 Abstract Full Text PDF PubMed Scopus (188) Google Scholar , 2 Mavrikakis I. Sfikakis P.P. Mavrikakis E. et al. The incidence of irreversible retinal toxicity in patients treated with hydroxychloroquine - a reappraisal. Ophthalmology. 2003; 110: 1321-1326 Abstract Full Text Full Text PDF PubMed Scopus (202) Google Scholar However, in 2010 Wolfe and Marmor estimated that the prevalence of HCR among those taking the drug for over 5 years was 1% and higher with longer-duration use. 3 Wolfe F. Marmor M.F. Rates and predictors of hydroxychloroquine retinal toxicity in patients with rheumatoid arthritis and systemic lupus erythematosus. Arthritis Care Res. 2010; 62: 775-784 Crossref PubMed Scopus (210) Google Scholar In 2014, Melles and Marmor reported a prevalence of 7.5% after 5 years of use, based on 10-2 visual field (VF) and spectral-domain optical coherence tomography (SDOCT) testing. 4 Melles R.B. Marmor M.F. The risk of toxic retinopathy in patients on long-term hydroxychloroquine therapy. Arch Ophthalmol. 2014; 132: 1453-1460 Google Scholar When the definition of retinopathy has been based on multifocal electroretinography (mfERG), reported prevalences have ranged as high as 33%. 5 Cukras C. Huynh N. Vitale S. Wong W.T. Ferris III, F.L. Sieving P.A. Subjective and objective screening tests for hydroxychloroquine toxicity. Ophthalmology. 2015; 122: 356-366 Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar The Prevalence of Hydroxychloroquine Retinopathy and Toxic Dosing, and the Role of the Ophthalmologist in Reducing BothAmerican Journal of OphthalmologyVol. 170PreviewThe recent editorial by Browning1 brings welcome attention to the ophthalmologist's role in screening for hydroxychloroquine (HCQ) toxicity and the need for careful dosing. However, we are concerned that it perpetuates incorrect information and omits important new evidence. Full-Text PDF