Retinopathy screening guidelines don't agree: antimalarial drugs.
The American Academy of Ophthalmology (AAO) guidelines, issued in 2002, note that hydroxychloroquine (Plaquenil) retinopathy appears to be an exceptionally rare adverse event, and that after a baseline, exam patients taking the drug may be screened as little as once over the next 10 years, as long as they are low risk (Ophthalmology 109:1377-82, 2002).
Treatment of rheumatologic disorders accounts for a large share of U.S. prescribing of antimalarials, but the AAO guidelines point out that the first reports of retinal toxicity concerned the long-term use of chloroquine for malaria.
In a prospective cohort study published after the AAO guidelines were issued, among 526 patients taking hydroxychloroquine for rheumatoid arthritis and systemic lupus erythematosus, not a single patient developed retinopathy within the first 5 years of treatment.
Two patients, who were treated for 6.5 and 8 years, did develop maculopathy, and the overall incidence of retinopathy among the 400 patients who were treated at recommended dosages for a mean of 8.7 years was 0.5% (Ophthalmology 110:1321-26, 2003).
Such findings shore up the AAO recommendations, which after a baseline exam, favor less frequent retinopathy screening compared with those recently released by the American College of Rheumatology (ACR).
The AAO recommends that screening frequency be risk based. For low-risk patients, screening frequency should be based on the patient's age and should be no different from that recommended for healthy individuals. For example, persons aged 20-29 years should be screened for retinopathy once during that 10-year period, and those aged 40-64 years should be examined every 2-4 years.
The AAO recommends annual screening for high-risk patients, a category that includes patients taking more than 6.5 mg/kg of hydroxychloroquine, patients using the drug for more than 5 years, patients who are obese or who have kidney or liver disease, and patients over the age of 60.
The ACR recommendations advise that after a normal baseline exam, all patients on hydroxychloroquine receive an eye exam at least annually, regardless of their risk.
But experts are quick to point out that neither recommendation is supported by data.
The bottom line is that "there are no data to justify any screening," said Dr. Liana Fraenkel, a rheumatologist at Yale University, New Haven, in an interview. "Usually if you're going to recommend screening ... you have a reasonable body of evidence, whether it's based on one fantastic randomized controlled trial or several smaller studies, showing the benefit of a screening strategy. There are no studies like that whatsoever on screening for hydroxychloroquine retinopathy," she said.
What little support there is for screening stems from case reports during the 1950s when people started using high doses of antimalarials and physicians started noticing changes in the back of their patients" eyes.
"But there's no evidence that the way we [now] prescribe hydroxychloroquine is associated with any changes over the baseline rate of change. And there have never been any studies showing the efficacy of screening. None," she added.
Dr. Oscar Gluck, director of the Arizona Rheumatology Center in Phoenix, said that despite the guidelines, he plans to continue sending his patients for screening every 6-12 months. He cited several justifications for ophthalmologic exams other than screening for hydroxychloroquine retinopathy:
Patients with systemic lupus or rheumatoid arthritis need to be assessed for Sjogren's syndrome, uveitis, retinal vasculitis, increased intraocular pressure, and other problems.
There's also the worry that the guidelines wouldn't provide enough of a legal defense in a court of law, given the fact that it's customary to err on the side of more frequent screening. Despite what the guidelines say, there's still a sense that it's the standard of care to screen patients more frequently. The concern is that if eye complications develop and regular screening wasn't done, then one's treatment may fall below the standard of care in the eyes of the court, Dr. Gluck added.
In any case, choices about the frequency of screening often are in the hands of the ophthalmologist, Dr. Fraenkel noted. "It's the ophthalmologist who asks for the return visit. Even if I asked for it less often, the ophthalmologists are in charge." In her experience, many ask for return visits every 6 months, despite their own academy's guidelines.
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|Title Annotation:||Clinical Rounds|
|Comment:||Retinopathy screening guidelines don't agree: antimalarial drugs.(Clinical Rounds)|
|Publication:||Family Practice News|
|Date:||Jan 15, 2004|
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