Medicare Advantage's 14% cost premium yields no diabetes gains, study finds

A JAMA Internal Medicine study of 35,000 adults with Type 2 diabetes found Medicare Advantage enrollees showed no improvement in key biomarkers despite extra benefits, even as the U.S. spends 14% more per enrollee than on traditional Medicare.

"Even though these benefits exist on paper for people, they're probably not reaching a lot of people," said Seth Berkowitz, lead researcher and primary care physician at UNC Health in Chapel Hill, N.C.

The observational study tracked participants for 3.5 years. The 45% who enrolled in a Medicare Advantage plan during that period saw no improvements in hemoglobin A1C, blood pressure, or LDL cholesterol compared with those on traditional Medicare. About 10 million seniors enrolled in plans with a food and produce benefit in 2025, yet three in 10 Medicare Advantage enrollees didn't use any supplemental benefits in 2024, and less than 10% used their grocery allowance or meal delivery benefits, according to the Commonwealth Fund.

Medicare Advantage plans now cover 55% of all Medicare beneficiaries, and supplemental benefits are a primary marketing tool for private insurers. The U.S. spends 14% more per Medicare Advantage enrollee than on traditional Medicare, partly due to "coding intensity" — the inclusion of more diagnoses that raise risk scores and increase payments. The findings raise questions about whether that additional spending delivers measurable value as open enrollment for 2026-27 approaches.

The study, published in JAMA Internal Medicine, examined whether people who enroll in Medicare Advantage plans see improvements in hemoglobin A1C, blood pressure, LDL cholesterol, and other common biomarkers associated with Type 2 diabetes. The researchers tracked 35,000 adults for 3.5 years and found that the 45% who enrolled in a Medicare Advantage plan during that time didn't see improvements in these measures. The study didn't identify a specific cause, but Berkowitz wondered if the supplemental benefits that appeal to seniors with diabetes — like food allowances and prepaid cards for over-the-counter diabetes supplies — aren't always easy to access.

The findings add to a growing body of research questioning whether Medicare Advantage's extra spending improves chronic condition management. A 2022 study similarly found that enrolling in a Medicare Advantage plan didn't lead to improvements in older adults with diabetes. Diabetes affects about 20% of older adults.

Supplemental benefits fall short

Medicare Advantage plans are offered by private health-insurance companies as an alternative to traditional Medicare. In exchange for narrower networks and stricter prior-authorization rules, enrollees can choose plans with extra benefits such as dental and vision coverage, prepaid debit cards for healthy food, or transportation to doctor visits. About 10 million seniors enrolled in plans with a food and produce benefit in 2025.

Sachin Jain, CEO of the nonprofit health insurer SCAN Group, which announced this week it's developing a Medicare Advantage plan with Costco, said the supplemental benefit experience is one of the most challenged areas in Medicare. "Many people feel like they've been subjected to a bait-and-switch in supplemental benefits," he said. "Plans will market themselves with really fancy, really generous-sounding supplemental benefits, and then when people go to use them, they realize that there's a restricted network, or they'll realize that the $1,000 of over-the-counter credits that they've been given come with inflated prices."

14% spending gap draws scrutiny

Medicare Advantage enrollees tend to be sicker and poorer than those on traditional Medicare, which partly explains higher costs. But Medpac, the independent agency that advises Congress on Medicare, attributes part of the 14% spending gap to coding intensity — the inclusion of more diagnoses for Medicare Advantage enrollees. These diagnoses feed into a risk score for each enrollee; the higher the risk score, the higher the payment.

"That higher spending could be worthwhile if it is accompanied by better health," Berkowitz and the other researchers wrote.

For seniors weighing plan choices during open enrollment, the study suggests that supplemental perks alone shouldn't drive the decision. The trade-off between narrower networks and stricter prior-authorization rules on one hand, and grocery credits and gym memberships on the other, may not deliver the health outcomes that marketing materials promise. As Medicare Advantage plans continue to attract a majority of beneficiaries, the pressure on policymakers to scrutinize both supplemental benefits and payment accuracy is likely to intensify. Readers should verify Medicare plan details against the latest official CMS announcements.

This content is for informational reference only and does not constitute professional advice.