Medicare Advantage Denies Rehab Care at Alarming Rates: What You Must Know

If you or a loved one has ever been discharged from a hospital and needed time in a skilled nursing facility or inpatient rehabilitation center, you already know how critical that transition can be. What you may not know is that if you're enrolled in a Medicare Advantage plan — the private insurance alternative to original Medicare — your insurer has the legal authority to require prior authorization before approving that care. And they are using that authority at rates that should concern every Medicare beneficiary in America.

Prior authorization is the process by which a private insurer must approve a medical service before it is delivered. In traditional Medicare — the government-run program under Parts A and B — prior authorization is rarely required for skilled nursing facility stays or inpatient rehabilitation. If your doctor says you need it and you meet the clinical criteria, you generally get it. Medicare Advantage operates differently. These plans, offered by private insurers like UnitedHealthcare, Humana, Aetna, and Blue Cross Blue Shield affiliates, are paid a fixed monthly amount per enrollee by the federal government and are permitted to manage care through tools like prior authorization, step therapy, and network restrictions.

The result, documented repeatedly in federal oversight reports and independent research, is a pattern of denials for post-acute care that leaves patients in limbo — sometimes discharged from hospitals before they are medically ready to go home, or forced to fight for coverage while they are at their most vulnerable. According to CMS.gov data from the Medicare Advantage prior authorization and claims denial landscape, Medicare Advantage organizations denied approximately 6.6% of prior authorization requests in 2021 — but the denial rates for specific service categories like skilled nursing facility care and inpatient rehabilitation were considerably higher than that aggregate figure, with some plans and some regions showing denial rates well above 10% for these post-acute services. The same CMS data showed that when beneficiaries appealed those denials, plans overturned their own decisions in a significant share of cases — a finding that strongly suggests many initial denials were not clinically justified.

To understand why this matters so much, consider what skilled nursing facility care actually involves. After a qualifying hospital stay of at least three days, Medicare covers up to 100 days in a skilled nursing facility per benefit period. Under traditional Medicare, days 1 through 20 are covered at 100% with no cost to you. Days 21 through 100 require a daily coinsurance payment — in 2025, that coinsurance is $204.00 per day. Under Medicare Advantage, your plan may cover the same 100-day window, but it can require prior authorization at any point during that stay, meaning your insurer can review your case and decide you no longer meet their criteria for continued coverage — even if your doctor disagrees. This is sometimes called a "mid-stay denial," and it can result in you being told you must leave a facility or begin paying out of pocket with very little warning.

Inpatient rehabilitation facilities, which provide intensive therapy for patients recovering from strokes, hip replacements, major surgeries, or serious injuries, face similar dynamics. These facilities require patients to be able to tolerate at least three hours of therapy per day, and they are staffed by physicians, physical therapists, occupational therapists, and speech-language pathologists working in coordination. Under traditional Medicare Part A, coverage for inpatient rehab follows the same structure as skilled nursing — no prior authorization required if clinical criteria are met. Under Medicare Advantage, prior authorization is almost universally required, and denial rates for these admissions have drawn scrutiny from the HHS Office of Inspector General, which found in a 2022 report that some Medicare Advantage denials for post-acute care met Medicare coverage rules and should have been approved.

Data Snapshot: According to CMS.gov Medicare Advantage plan data, more than 3,900 Medicare Advantage plans were available to beneficiaries nationally in 2024, with enrollment exceeding 33 million people — representing roughly 51% of all Medicare-eligible individuals. That means more than half of all Medicare beneficiaries are now in plans that can use prior authorization to manage access to post-acute care. CMS star ratings data for 2024 shows that fewer than 20% of Medicare Advantage contracts earned 4.5 stars or higher, the threshold that triggers bonus payments to insurers — meaning the majority of plans are operating at average or below-average quality levels even by the industry's own benchmarks.

So what can you actually do about this? First, before you need rehab care is the best time to review your plan's prior authorization requirements. Every Medicare Advantage plan is required to publish its prior authorization policies, and you can find them in your plan's Evidence of Coverage document — a detailed booklet your insurer must provide annually. Look specifically for the sections covering skilled nursing facility care and inpatient rehabilitation. If your plan requires prior authorization for these services, find out how that process works: who initiates it (typically your hospital's discharge planner or case manager), how quickly the plan must respond (federal rules require a decision within 72 hours for urgent requests), and what criteria the plan uses to evaluate medical necessity.

If your Medicare Advantage plan denies a prior authorization request for skilled nursing or rehab care, you have specific appeal rights that are worth understanding in detail. The first level of appeal is a redetermination, which you must request within 60 days of the denial notice. For urgent situations — meaning your health could be seriously harmed by waiting — you can request an expedited appeal, and the plan must respond within 72 hours. If the plan upholds the denial, you can escalate to an independent review organization, which is a third party contracted by CMS that is not affiliated with your insurer. Studies have consistently shown that beneficiaries who appeal Medicare Advantage denials win a meaningful percentage of those appeals — which is why filing an appeal, rather than simply accepting a denial, is almost always worth doing.

Your hospital's discharge planning team is one of your most important allies in this process. Case managers and social workers at hospitals deal with Medicare Advantage prior authorization requirements every day, and they know which plans in your area tend to approve or deny post-acute care requests. If you are being discharged and your plan has denied a skilled nursing facility stay that your doctor believes is medically necessary, ask the hospital's case manager to help you initiate an appeal immediately. You also have the right to request a written notice of non-coverage, which starts the formal appeal clock and ensures you have documentation of the denial.

For beneficiaries who are weighing their options during the Annual Enrollment Period — which runs October 15 through December 7 each year — the denial rate issue is a legitimate factor to consider when choosing between Medicare Advantage and traditional Medicare. Traditional Medicare paired with a Medigap supplemental insurance policy (also called Medicare Supplement Insurance) typically offers broader access to skilled nursing facilities and inpatient rehab because there is no prior authorization requirement and no network restriction. The tradeoff is cost: Medigap premiums vary significantly by plan letter, age, and state, but a Plan G policy — currently the most comprehensive Medigap option for new enrollees — may cost anywhere from $100 to $300 or more per month depending on your age and location, according to CMS.gov and state insurance department rate filings. That is a real expense, but for someone with a history of cardiac events, orthopedic problems, or neurological conditions that frequently require post-acute rehabilitation, the predictability of coverage may outweigh the premium cost.

If you are already enrolled in Medicare Advantage and want to switch to traditional Medicare, the Annual Enrollment Period (October 15–December 7) allows you to make that change, with coverage starting January 1. There is also the Medicare Advantage Open Enrollment Period, which runs January 1 through March 31, during which you can switch from one Medicare Advantage plan to another or drop Medicare Advantage and return to traditional Medicare. Be aware that if you return to traditional Medicare after age 65 and want to add a Medigap policy, you may face medical underwriting in most states — meaning insurers can charge you more or deny coverage based on your health history. The exceptions are the birthday rule states, where you have a 30-day window each year around your birthday to switch Medigap plans without underwriting: California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, and Oregon.

CMS has taken steps in recent years to address the prior authorization problem. Starting in 2024, CMS implemented new rules requiring Medicare Advantage plans to use the same clinical criteria as traditional Medicare when making coverage decisions for services that Medicare covers. Plans are also now required to make prior authorization approvals "continuity of care" valid for the duration of a course of treatment, not just a single episode. These rules are meaningful, but enforcement depends on CMS audits and beneficiary complaints — which means the burden still falls partly on you to know your rights and push back when a denial seems unjustified.

If you want to compare Medicare Advantage plans by their denial rates and appeal outcomes, Medicare.gov's Plan Finder tool allows you to compare plans available in your ZIP code, including star ratings that incorporate measures of access to care and member complaints. You can also call 1-800-MEDICARE (1-800-633-4227) to speak with a counselor, or contact your State Health Insurance Assistance Program (SHIP) — a free, unbiased counseling service available in every state — to get personalized help reviewing your options. SHIP counselors are trained specifically to help Medicare beneficiaries understand their rights and navigate coverage disputes, including prior authorization denials for post-acute care.