More than one in four American adults struggle to afford their prescription medications. Those who can’t are left with grim choices — skipping doses, cutting pills in half, or abandoning prescriptions entirely.

New research from Richard A. and Susan F. Smith Center for Outcomes Research at Harvard-affiliated Beth Israel Deaconess Medical Center offers early evidence that federal drug pricing reforms intended to help are beginning to do just that.

Published in JAMA Internal Medicine, the study found that Medicare beneficiaries were less likely to report skipping, rationing, or foregoing medications due to cost after the Inflation Reduction Act’s prescription drug cost-cutting provisions took effect Jan. 1, 2024. The improvement was greatest among those managing multiple chronic conditions.

“For too long, Medicare patients have been forced to ration important medications because of cost. Our findings are an early signal that the Inflation Reduction Act is changing that — and the patients benefiting most are exactly those who need it most,” said the study’s senior author, Rishi K. Wadhera, associate director and section head of health policy at the Smith Center for Outcomes Research and an associate professor at Harvard Medical School.

The act’s 2024 provisions targeted two groups most burdened by drug costs. For Medicare beneficiaries with high medication spending, the law eliminated the 5 percent co-insurance requirement for catastrophic coverage, effectively capping annual out-of-pocket costs at approximately $3,300 per year. For lower-income enrollees who had been receiving only partial assistance, it expanded access to full subsidies, significantly reducing what they pay for their medications.

To assess the real-world impact of these changes, researchers used a quasi-experimental difference-in-differences design, drawing on data from the National Health Interview Survey, an annual survey of more than 27,000 U.S. adults conducted by the Centers for Disease Control and Prevention. Wadhera and colleagues compared Medicare Part D beneficiaries between the ages of 62 and 67 to a similar group of privately insured adults who were not subject to the act’s provisions.

They found that Medicare beneficiaries experienced a 4.9 percentage point reduction in cost-related medication nonadherence relative to their privately insured counterparts. Specifically, fewer patients reported skipping doses, reducing doses, delaying prescription fills, or foregoing medications because of cost. The finding held up across multiple sensitivity analyses, including after adjusting for race, ethnicity, income, and educational attainment, and when compared to a different comparison group (dually-enrolled beneficiaries).

The effect was particularly pronounced among beneficiaries managing two or more chronic conditions — including hypertension, diabetes, heart disease, and cancer — who saw a 7.8 percentage point reduction in cost-related nonadherence. Compare that to privately insured adults, not covered by the act’s provisions, for whom medication nonadherence rose more than 2 percentage points during the same period. As of June 30, 2024, 1.5 million Medicare beneficiaries had saved close to $1 billion from the act’s elimination of the catastrophic coverage co-insurance requirement alone.

“When someone with diabetes or heart disease stops taking their medications due to cost, the consequences can be severe. Our data suggest that the [Inflation Reduction Act’s] reforms are helping the highest-risk patients stay on the medications they need,” said lead author of the study, Lucas Marinacci, a faculty physician investigator at the Richard A. and Susan F. Smith Center for Outcomes Research, general cardiologist at BIDMC, and instructor at Harvard Medical School.

While the act’s drug provisions are helping Medicare beneficiaries stay on their medications, they are not yet making a dent in their overall health care costs. The study found neither a corresponding improvement in Medicare beneficiaries’ ability to pay medical bills nor a decrease in their anxiety about future health care costs.

The study was supported in part by the National Institutes of Health.