Study by SPH Grad Examines Effect of Cost-Sharing on Diabetes Drug Adherence.
The phase-out of the Medicare Part D coverage gap will have little effect on prescription adherence rates for people taking generic drugs, but patients using more costly branded medications remain vulnerable to cost-related non-adherence, according to a new study led by a recent BU School of Public Health graduate.
The study, published in the Journal of General Internal Medicine and led by Naomi Sacks, who received her PhD in January, evaluates the effects of cost-sharing in the Medicare Part D prescription drug program on anti-diabetic medication adherence. Sacks and her co-authors from the BU schools of public health and medicine found that cost-sharing has no effect on the use of inexpensive generic anti-diabetics, but could adversely affect adherence to more costly branded medications.
The Part D coverage gap (informally known as the Medicare “donut hole”) lies between the initial coverage limit and the catastrophic-coverage threshold in the Medicare Part D prescription-drug program. The U.S. Department of Health and Human Services estimates that more than a quarter of Part D participants stop following their prescribed regimen of drugs when they hit the donut hole. The 2010 Affordable Care Act seeks to address the coverage gap by creating discounts on brand-name and generic drugs purchased within the gap range. Between now and 2020, the gap will gradually be closed to a point where it is eliminated.
Sacks said that while closing the gap will have positive impacts for many patients, co-payments for more costly branded drugs may stymy improvements in adherence rates.
“High copayments prior to and in the coverage gap may continue to adversely affect branded medication adherence,” she and her co-authors said. “Benefit structure modifications that remove cost-related medication use deterrents are needed, as are initiatives that address non-cost factors” contributing to lapses in adherence for less expensive generic products.
The study examined variations in adherence rates to different groupings of anti-diabetic medications, two of them branded and expensive (average prescription price over $200), and two that were primarily generic and cheaper ($13-$15, on average). Sacks said the study found that most diabetic patients were using the generic medications, so “the good news is that we didn’t see cost-related non-adherence” for the majority of patients in the study sample.
“Generic drugs are recommended as first- and second-line therapies in diabetes – and it looks like those guidelines are being followed,” she said. But the effects on adherence to the more expensive branded drugs were significant and “of some concern, because patients are typically prescribed the branded medications if and when the generics aren’t effective,” usually because they have more complex forms of the disease.
The study was part of Sacks’ dissertation, and she credits her co-authors for providing “critical guidance” for her research. They include: James Burgess, professor of health policy and management; Howard Cabral, professor of biostatistics; Steven Pizer, research associate professor of health policy and management; and Dr. Marie McDonnell of the Department of Medicine, Section of Endocrinology, Boston Medical Center.
Submitted by: Lisa Chedekel
chedekel@bu.edu