If you're enrolled in a Medicare Advantage plan, you've probably encountered prior authorization — the process where your insurer must approve a procedure, specialist visit, imaging study, or piece of medical equipment before you can receive it. What many beneficiaries don't realize is that federal law now requires every Medicare Advantage insurer to publicly report exactly how often it approves or denies those requests, and how fast it responds. For the first time, that data covers the full 2025 calendar year, and the numbers raise serious questions about whether seniors are getting the access they're paying for.
The headline figure: Medicare Advantage insurers denied 12% of standard prior authorization requests in 2025. That means roughly 1 in 8 requests for services — MRIs, home health visits, skilled nursing facility stays, durable medical equipment, outpatient rehabilitation — was initially turned down. Insurers were required to post this data publicly by March 31, 2026, under a final rule published by the Centers for Medicare and Medicaid Services in 2024. The rule, formally titled the CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F), marked the first time standardized prior authorization metrics became available for public comparison across the Medicare Advantage market.
To put 12% in context: Medicaid managed care plans denied 14% of standard prior authorization requests over a comparable period, and ACA Marketplace insurers denied 18%. Medicare Advantage performs somewhat better than those markets on this single measure. But context only goes so far when you look at what happens the moment a beneficiary actually challenges a denial. Of all prior authorization denials that were appealed in Medicare Advantage in 2025, 67% were overturned — meaning two out of every three denials that beneficiaries contested were reversed in the beneficiary's favor. That is not a rounding error. It is a signal that a substantial share of initial denials either lack solid clinical justification or fail to hold up when subjected to even basic scrutiny.
The deeper problem is that most denials are never appealed at all. When a 74-year-old recovering from a hip replacement receives a letter saying her insurer won't authorize additional home health visits, she may assume the decision is final. She may not know she has appeal rights, may not have the energy to fight a bureaucratic process while managing her recovery, or may simply not know where to start. This is the dynamic that consumer advocates and health policy researchers have documented for years: prior authorization burdens fall hardest on the people least equipped to bear them. The 67% overturn rate is only meaningful if beneficiaries actually use the appeals process — and right now, most don't.
According to CMS.gov data, approximately 7,900 Medicare Advantage plans were available to beneficiaries nationwide in 2025, offered by insurers ranging from national carriers like UnitedHealthcare, Humana, and CVS Health (Aetna) to dozens of regional and local plans. The average Medicare beneficiary has access to 43 Medicare Advantage plans in their county, according to KFF analysis of CMS plan data. With that many options, comparing prior authorization practices has historically been nearly impossible during the Annual Enrollment Period, which runs October 15 through December 7 each year. The new reporting requirement changes that — at least in principle — by giving beneficiaries a standardized metric to look up before they commit to a plan for the coming year.
The practical limitation is that the data is highly aggregated. Insurers post overall approval and denial rates across all medical items and services combined. They are not currently required to break down denial rates by service category, diagnosis, or patient demographic. That means you can learn that a particular Medicare Advantage insurer denied 15% of prior authorization requests overall in 2025, but you cannot determine whether that insurer has an especially high denial rate for cardiac rehabilitation, outpatient physical therapy, or home health services — three categories that matter enormously to many Medicare beneficiaries. Policy researchers and patient advocates are actively pushing CMS to require more granular reporting in future rulemaking, but for now, the aggregate figures are what's available.
Response times are a second metric now being publicly reported, and they carry real clinical weight. Under existing Medicare Advantage rules, insurers must respond to standard prior authorization requests within 14 calendar days and to expedited requests within 72 hours. The new data reveals variation in how quickly different insurers actually respond within those windows, and even technically compliant delays can cause genuine harm — a patient waiting 13 days for approval of a skilled nursing facility transfer, for example, may face a longer hospital stay, a missed rehabilitation window, or a family forced to make care decisions without complete information. The 2024 CMS rule was designed in part to accelerate decision-making through electronic prior authorization systems, and the publicly posted response time data will allow regulators and researchers to track whether that acceleration is actually occurring.
Data Snapshot: According to CMS.gov data on Medicare Advantage plan availability, the number of Medicare Advantage plans offered nationally grew from roughly 3,834 in 2018 to approximately 7,900 in 2025 — more than doubling in seven years. Over that same period, Medicare Advantage enrollment grew from 20.4 million to more than 33 million beneficiaries, representing more than half of all Medicare enrollees for the first time. The scale of that enrollment makes prior authorization practices a population-level issue: a 12% denial rate applied across tens of millions of authorization requests each year translates to millions of individual coverage decisions that may be contested, delayed, or simply abandoned.
If you receive a prior authorization denial right now, here is exactly what your rights are. You have the right to appeal, and the timeline depends on urgency. For a standard appeal, your plan must respond within 60 days of receiving your request. For an expedited appeal — which you can and should request if your physician certifies that waiting the standard timeline would seriously jeopardize your health or ability to regain maximum function — the plan must respond within 72 hours. If your plan upholds the denial at the first level, you can escalate to an Independent Review Organization, which is a federally contracted entity that reviews the case independently of your insurer. If the IRO also upholds the denial and the amount in dispute exceeds $180 (a threshold that adjusts annually with inflation), you can request a hearing before an administrative law judge. The 67% overturn rate at the first appeal level means that filing an appeal is not a long shot — it is the statistically likely path to getting the care your doctor recommended.
When you appeal, documentation is everything. Ask your physician to submit a letter of medical necessity that specifically addresses the insurer's stated reason for denial. Many physician offices have staff who handle prior authorization appeals routinely and know exactly what language insurers respond to. If your doctor's office doesn't have that capacity, your State Health Insurance Assistance Program — known as SHIP — offers free, one-on-one counseling to Medicare beneficiaries navigating exactly these situations. You can find your state's SHIP contact through Medicare.gov or by calling 1-800-MEDICARE.
For beneficiaries approaching the Annual Enrollment Period this fall, the new prior authorization data offers a concrete comparison point beyond premiums and star ratings. When you use Medicare.gov's Plan Finder tool to compare options in your ZIP code, you can note each plan's insurer and then visit that insurer's website to review their publicly posted prior authorization metrics. A plan with a 9% denial rate and an average response time of 6 days may offer meaningfully better access to care than a plan with a 17% denial rate and a 12-day average response time — and that difference in access can matter far more than a $30 difference in monthly premium if you have a chronic condition, anticipate surgery, or rely on home health services.
Prior authorization requirements also vary significantly from plan to plan, even among plans offered by the same insurer in the same county. One Medicare Advantage HMO might require prior authorization for outpatient physical therapy after the fifth visit; a PPO from the same insurer might not require it at all. These requirements are disclosed in each plan's Evidence of Coverage document — a detailed but essential document that every enrollee receives at enrollment and annually thereafter. If you have a condition requiring ongoing specialist care, imaging, or home health services, reviewing the prior authorization section of a plan's Evidence of Coverage before you enroll is one of the highest-value steps you can take during the Annual Enrollment Period.
The broader policy landscape is still developing. The 2024 CMS rule was a meaningful first step toward transparency, but consumer advocates are pushing for the next step: denial rates broken down by service type, diagnosis category, and demographic group, along with stronger enforcement when insurers are found to be systematically denying appropriate care. There are also active legislative proposals in Congress that would prohibit prior authorization for certain emergency services and require continuity of care when a beneficiary switches plans mid-year. Whether those proposals advance will depend on the political environment, but the new public data gives advocates a factual foundation they did not previously have.
The single most important thing to take away from this new data is straightforward: a prior authorization denial is not the final word. A 67% overturn rate is not a statistical footnote — it is evidence that the appeals process works, and that beneficiaries who advocate for themselves are far more likely to receive the care their doctors recommended. Do not accept a denial letter as a closed door. Ask your doctor to help you appeal, gather your clinical documentation, and contact your state SHIP program if you need free guidance navigating the process. The system is designed to be difficult to navigate, but it is not designed to be impossible — and the data shows that persistence pays off.