Hydroxychloroquine can be used safely and effectively with attention to dosing, risk factors, and screening, but communication among physicians, patients, and eye care specialists is key to optimizing outcomes and preventing complications, according to a joint statement from four medical societies.
Dr. James T. Rosenbaum
The American College of Rheumatology, American Academy of Dermatology, Rheumatologic Dermatology Society, and the American Academy of Ophthalmology have produced a statement, published in Arthritis & Rheumatology, “to emphasize points of agreement that should be recognized by practitioners in all specialties,” lead author James T. Rosenbaum, MD, of Oregon Health & Science University, Portland, and colleagues wrote.
The statement was developed by a working group that included rheumatologists, ophthalmologists, and dermatologists with records of published studies on the use of hydroxychloroquine (HCQ) and its toxicity. The statement updated elements of the 2016 American Academy of Ophthalmology guidelines for monitoring patients for retinal toxicity when using HCQ.
“The need for collaborative management has triggered this joint statement, which applies only to managing the risk of HCQ retinopathy and does not include consideration of cardiac, muscle, dermatologic, or other toxicities,” the authors noted.
The authors emphasized that HCQ plays a valuable role in controlling many rheumatic diseases, and should not be abandoned out of fear of retinopathy. However, proper dosing, recognition of risk factors, and screening strategies are essential.
Dosing data
Data on HCQ dosing and retinopathy are limited, but the authors cited a study of 2,361 rheumatic disease patients with an average HCQ dosing regimen of 5.0 mg/kg per day or less in which the toxicity risk was less than 2% for up to 10 years of use. Although data show some increase in risk with duration of use, “for a patient with a normal screening exam in a given year, the risk of developing retinopathy in the ensuing year is low (e.g., less than 5%), even after 20 years of use,” the authors said.
Risk factor recognition
“High daily [HCQ] dosage relative to body weight and cumulative dose are the primary risk factors for retinopathy,” the authors noted. Reduced renal function is an additional risk factor, and patients with renal insufficiency should be monitored and may need lower doses.
In addition, patients with a phenotype of initial parafoveal toxicity may be at increased risk for advanced disease evidenced by damage to the foveal center. “The phenotype of initial parafoveal toxicity is not universal, and in many patients (East Asians particularly) the retinal changes may appear initially along the pericentral vascular arcades,” so these patients should be screened with additional tests beyond the central macula, they emphasized.
Screening strategies
Patients should receive a baseline retinal exam within a few months of starting HCQ to rule out underlying retinal disease, according to the statement. The goal of screening is “to detect early retinopathy before a bullseye becomes visible on ophthalmoscopy, since at that severe stage the damage tends to progress even after discontinuing the medication and may eventually threaten central vision,” the authors said.
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In the absence of risk factors, patients can defer screening for 5 years, but should be screened annually from 5 years and forward, they said. Examples of underlying retinal disease include “significant macular degeneration, severe diabetic retinopathy, or hereditary disorders of retinal function, but these are judgments best made by the ophthalmologist since mild and stable abnormalities that do not interfere with interpretation of critical diagnostic tests may not be a contraindication” to use of HCQ.
The consensus opinion statement has limitations, notably the shortage of data on optimum HCQ dosage and the lack of prospective studies of toxicity, including the need for studies of the impact of blood levels on toxicity and studies of pharmacogenomics to stratify risk, the authors noted.
“It is important that the drug is not stopped prematurely, but also that it is not continued in the face of definitive evidence of retinal toxicity except in some situations with unusual medical need,” they said.
“Suggestive or uncertain findings should be discussed with the patient and prescribing physician to justify further examinations, but the drug need not be stopped until evidence for retinopathy is definitive, in particular for patients with active rheumatic or cutaneous disease,” and the overall risk of retinopathy remains low if the principles described in the statement are followed, they concluded.
First author Dr. Rosenbaum disclosed financial relationships with AbbVie, UCB, Gilead, Novartis, Horizon, Roche, Eyevensys, Santen, Corvus, Affibody, Kyverna, Pfizer, Horizon, and UpToDate. Another 5 of the study’s 11 authors also disclosed relationships with multiple companies.