Sicker Seniors Are Fleeing Medicare Advantage for Traditional Medicare, Study Finds. Nursing Homes Are Watching.

A new study published in JAMA Health Forum is raising fresh questions about how well Medicare Advantage serves seniors once they get seriously sick. Researchers found that older adults who develop new, complex medical conditions are more likely to leave their Medicare Advantage plans and return to traditional Medicare. The pattern intensifies as their medical complexity grows.

The findings carry real weight for nursing homes. Long-stay nursing home residents are increasingly enrolled in Medicare Advantage. In 2023, 36.5% of those residents were in MA plans, according to data published in the Journal of the American Geriatrics Society. That share has climbed steadily, and operators have long complained that MA plans can be slower to approve post-acute care and more restrictive on referrals than traditional Medicare.

What the research shows

The study tracked Medicare enrollment and medical claims from 2016 through 2021. Researchers compared beneficiaries who stayed healthy with those who developed a new complex condition between 2019 and 2021. The list of complex conditions included Alzheimer disease, stroke, congestive heart failure, chronic kidney disease, chronic obstructive pulmonary disease, and acute myocardial infarction, among others.

Beneficiaries who developed these conditions were significantly more likely to disenroll from their MA plan and switch to traditional Medicare. The effect was strongest in states with Medigap community-rating and guaranteed-issue protections, which make it easier for sicker seniors to buy supplemental coverage without being charged more or denied outright.

Within Medicare Advantage, enrollees in health maintenance organization plans were also more likely to switch plans than those in other types of MA coverage.

Why operators are watching

About 32.8 million Americans are enrolled in Medicare Advantage, and roughly 90% of them are 65 or older, according to MedPAC’s 2026 data book. As the program has grown, so has its footprint in skilled nursing facilities. Operators now routinely navigate MA prior-authorization requirements, narrow networks, and payment disputes alongside the agency’s recent quality-reporting push.

If sicker seniors continue to migrate back to traditional Medicare, nursing homes could see shifts in admission sources, prior-authorization burdens, and reimbursement timelines. Traditional Medicare generally pays providers more directly and with fewer pre-approval hurdles than many MA plans, though it also leaves beneficiaries exposed to higher out-of-pocket costs without supplemental coverage.

The study does not conclude that Medicare Advantage is failing seniors. But it does suggest that the program may struggle to retain enrollees precisely when they need the most care. For nursing homes, that volatility in payer mix is worth tracking closely.