In 2024, Medicare Advantage insurers made nearly 53 million prior authorization determinations, up from 49.3 million the year before, according to a KFF analysis of CMS data released in January 2026. Roughly 8% of those requests were fully or partially denied.
Here is the number that should bother every revenue cycle leader more than the denial rate itself: only 11.5% of denied requests were ever appealed. Of the ones that were, 80.7% were partially or fully overturned. A more recent KFF analysis of 2025 prior authorization metrics puts the standard-request overturn rate in Medicare Advantage at 67%, compared with 47% in Medicaid managed care and 43% in the ACA marketplace. Put plainly, when a denial gets challenged, it is wrong more often than it is right, and most practices are not challenging it.
That gap tracks with what physicians report about the process upstream of any appeal. In the 2025 AMA Prior Authorization Physician Survey, 95% of physicians said prior authorization delays access to necessary care, 79% said patients abandon treatment because of it, and 26% reported that PA contributed to a serious adverse event for a patient, including hospitalization or permanent harm.
Oncology shows the sharpest version of this pattern. In an ASCO survey of Association for Clinical Oncology members, 96% reported that prior authorization delayed treatment, 80% said it contributed to disease progression, and 36% linked it to a patient death. A separate 2024 survey of more than 750 radiation oncologists found 92% saw treatment delays tied to prior authorization, with delays lasting five days or longer for most of them, up from about half in 2020.
None of this means every denial is wrong or every appeal will win. It means the data does not support treating a denial as the end of the conversation. An 80.7% overturn rate on appealed Medicare Advantage denials is a strong argument for building appeals into the standard workflow rather than reserving them for a handful of high-dollar cases. The practices closing that gap are the ones tracking denial reasons by payer and service line, and appealing on a schedule instead of by exception.
Sources
- KFF, Medicare Advantage Insurers Made Nearly 53 Million Prior Authorization Determinations in 2024, Jan 2026
- KFF, Prior Authorization Metrics Provide New Insights Into Insurer Practices
- AMA, 2025 Prior Authorization Physician Survey, May 2026
- ASCO, Nearly All Oncology Providers Report Prior Authorization Causing Delayed Care, Other Patient Harms
- The ASCO Post, Prior Authorization Delays May Lead to Severe Consequences for Patients With Cancer, Dec 2024
