Rates and predictors of hydroxychloroquine (Plaquenil) retinal toxicity in RA and SLE

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Arthritis Care Res (Hoboken). 2010 Jun;62(6):775-84.

Rates and predictors of hydroxychloroquine retinal toxicity in

patients with rheumatoid arthritis and systemic lupus erythematosus.

Wolfe F, Marmor MF.

National Data Bank for Rheumatic Diseases and University of Kansas

School of Medicine, Wichita, KS 67214, USA.

Abstract

OBJECTIVE: Hydroxychloroquine (HCQ) retinopathy is of concern because

of the potential seriousness of visual loss and the medicolegal

consequences of failure to detect toxicity. However, there have been

limited demographic data on which to base recommendations for

screening. We have studied the largest unselected series of patients

to date to evaluate the risk of toxicity and the relevance of

purported risk factors.

METHODS: We studied 3,995 patients with rheumatoid arthritis or

systemic lupus erythematosus who had used HCQ, including 1,538 current

users. We screened for self-reported toxicity, and followed up on

positive cases with detailed interviews and specialist confirmation.

We categorized cases as " definite or probable " if there was bull's eye

maculopathy or visual field loss.

RESULTS: Of the lifetime users of HCQ, 6.5% discontinued therapy

because of an eye problem, including 1.8% who reported HCQ retinal

problems. However, definite or probable toxicity was documented in

only 0.65% (95% confidence interval 0.31-0.93). The risk of toxicity

was low in the initial 7 years of exposure, and was approximately 5

times greater after 7 years of usage (or 1,000 gm total exposure).

Toxicity was unrelated to age, weight, or daily dosage. Eye

examinations were obtained annually by 50.5% and every 6 months by

40.4% of patients.

CONCLUSION: HCQ toxicity remains uncommon, but increases markedly with

the duration of therapy and exceeds 1% after 5-7 years. Toxicity was

unassociated with age, daily dosage, or weight. These findings will

aid the reformulation of screening guidelines.

PMID: 20535788

http://www.ncbi.nlm.nih.gov/pubmed/20535788

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