Overview
- The KFF analysis, published Thursday, Aug. 13, 2026, used CMS-mandated reports to calculate that insurers denied between roughly 12% and 18% of standard prior-authorization requests across Medicare Advantage, Medicaid managed care and ACA marketplace plans in 2025.
- Denial rates varied sharply by payer and market with examples including UnitedHealth Group at 17% in Medicare Advantage, Centene at 25% in the ACA marketplace and Independence Health Group at 23% in Medicaid managed care.
- When denied requests were appealed they were overturned at high rates—about 67% in Medicare Advantage, 47% in Medicaid managed care and 43% in the ACA marketplace—while appeals themselves remain uncommon.
- The published metrics stem from a CMS rule that required insurers to report denial rates, processing times and overturn rates for 2025 with the first reports due March 31, 2026, but the data are aggregated and omit service-level breakdowns and reasons for denials.
- Insurers have made some voluntary cuts or simplifications to prior authorization and more than 50 payers previously pledged reforms, but provider groups, advocates and regulators are pressing for clearer rules, more granular public data and possible limits to curb delays in patient care.