Diabetic Macular Edema: Pricey Option May Be Cost-Effective

Diedtra Henderson

August 03, 2012

August 3, 2012 — It may be cost-effective to treat patients who have diabetic macular edema (DME) with ranibizumab and deferred laser to enhance their vision, at an added cost of $19,216 compared with treating them with triamcinolone and laser. An article published in the August issue of Ophthalmology was based on data demonstrating vision improvements from this approach are maintained for at least 2 years. If follow-up studies show that the improvements are maintained for 10 years, the additional cost would meet accepted cost-effectiveness standards.

More than 25.8 million Americans, or 8.3% of the US population have diabetes, according to the National Diabetes Education Program. Among people living with diabetes in the United States, DME is the most common cause of visual impairment, and its prevalence is expected to rise, mirroring the nation's soaring diabetes rate.

Treating people with diabetes, including treating diabetic eye disease, contributes mightily to the nation's high annual healthcare costs, which are estimated to consume 17.6% of the gross domestic product. To that end, Vinay Dewan, MD, from the Department of Ophthalmology and Visual Sciences at Washington University School of Medicine in St. Louis, Missouri, and coauthors conducted the first economic evaluation of DME treatment involving anti–vascular endothelial growth factor agents and corticosteroids in an attempt to guide policymakers, insurance companies, and others who allocate medical resources.

Dr. Dewan and coauthors constructed a Markov decision model using microstimulation to estimate the cost-effectiveness of 4 treatment groups of a recently published study. The Diabetic Retinopathy Clinical Research Network (DRCRnet) Protocol I randomized controlled trial recently evaluated the use of ranibizumab and triamcinolone, finding that ranibizumab plus prompt or deferred laser yielded greater increases in visual acuity (VA). Visual outcomes in pseudophakic eyes were similar whether patients were treated with ranibizumab or triamcinolone, indicating reduced triamcinolone effectiveness resulting from lens toxicity associated with steroids.

The research team's 4 treatment groups matched those from the trial's Protocol I: sham injection plus laser therapy, intravenous ranibizumab plus laser therapy, intravenous ranibizumab plus deferred laser therapy, and intravenous triamcinolone plus laser therapy. They conducted their analysis from the payor's perspective, using 2010 Medicare allowable charges for their costs, and estimated the cost per letter gained. Using ranibizumab with deferred laser to treat phakic patients with DME enhanced the sharpness of their vision by 6 letters at an additional cost of $19,216 over the course of 2 years, according to the study.

"The incremental cost per letter gained in VA was $393 (sham plus laser vs. triamcinolone plus laser), $5943 (ranibizumab plus prompt laser vs. sham plus laser), and $20 (ranibizumab plus deferred laser vs. ranibizumab plus prompt laser)," the authors write. At 2 years, the high cost of ranibizumab with deferred laser "is not likely to meet most accepted standards of cost-effectiveness," they acknowledge. "However, the economic benefit of treatment of DME is not experienced for only 2 years; it is experienced for the patient's remaining lifetime. When we extrapolate the experience of Protocol I participants beyond the trial, we find that by year 10 the benefits that the patient has enjoyed (in terms of years of useful vision) when compared with the cost of treatment over those years would be likely to meet the standards of cost-effectiveness in the United States."

In an interview with Medscape Medical News, Steven Kymes, PhD, MHA, director of the Center for Economic Evaluation in Medicine at Washington University School of Medicine and a study coauthor, said the key factor for specialists selecting a treatment for a patient who has DME is the patient's phakic status.

For patients with DME who retain their natural eye lens, ranibizumab is the better option. For patients with DME who have already undergone cataract surgery, the most cost-effective treatment choice is steroids, Dr. Kymes said.

In the article, Dr. Dewan and coauthors acknowledge that such economic evaluation studies have not been heavily relied on in the United States. Dr. Kymes noted that US decision making is far more decentralized than other countries, with coverage decisions made by public and private insurers and other payors.

"Trying to establish the cost-effectiveness of a particular treatment can be very difficult because different payors have different criteria for assessing the coverage of a drug, of which economic factors are only one," Dr. Kymes said. Still, he added, the work has application outside of the United States.

Sonal Singh, MD, MPH, an assistant professor in the Department of Medicine at Johns Hopkins University School of Medicine, in Baltimore, Maryland, called the article "useful" and "reasonably solid work." Dr. Singh found the conclusions "a little overstated," given the limited data and the research team's extrapolation from 2 years to 10 years, and added that the results may have differed had the researchers approached the question from a societal perspective, rather than a payor's perspective.

Still, such economic evaluations are warranted, Dr. Singh said, and also should be done for diabetes and kidney disease, diabetes and cardiovascular disease, and diabetes in general. The current article is a "step in the right direction," he said, because "diabetes is prevalent and has huge societal costs."

Study limitations included finding less statistical variation than the DRCRnet investigators reported. The research team explained that its model would become unstable if they incorporated the outliers reflected by the larger variance reported by the Protocol I group.

Dr. Kymes disclosed financial relationships with Genentech, manufacturer of ranibizumab, and Pfizer, and acts as a consultant for Allergan, Genentech, Pfizer, and TreeAge, the maker of the software used in the project. One coauthor acts as a consultant for Allergan, Alimera, Baxter, Eyetech, Genentech, Ophthotech, and Regeneron.

Ophthalmology. 2012;119:1679-1684. Abstract

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