Medicare Advantage, Medicaid managed care and federally facilitated ACA Marketplace health plans deny between 12% and 18% of standard prior authorization requests — denials that can act as a burden to home health providers.
Prior authorization denial rates varied widely among the largest insurers in 2025, according to a recent study by KFF.
“Health insurers use prior authorization to reduce the use of low-value or unnecessary care, and in the complex and fragmented U.S. health care system is one of the primary tools used to restrain costs,” the study’s authors wrote. “Nevertheless, this practice may result in delays or denials in receiving necessary care, as well as administrative burdens for patients and providers.”
San Francisco, California-based KFF is an independent health policy organization that researches Medicare, Medicaid and other health policy issues.
KFF analyzed publicly available prior authorization metrics for calendar year 2025 from 14 insurers. The data covered 25 million Medicare Advantage enrollees, 35 million Medicaid managed care organization enrollees and nearly 11 million federally facilitated ACA Marketplace enrollees.
Among the six largest Medicare Advantage insurers included in the analysis, standard-request denial rates ranged from 5% at Elevance to 17% at UnitedHealth Group. Expedited-request denial rates varied from 3% at Elevance to 13% at Centene.
Prior authorization denials are rarely appealed, the study found, but appeals are often successful. Among the insurers in KFF’s analysis, 67% of appealed standard-request denials were overturned in Medicare Advantage, compared with 47% in Medicaid managed care and 43% in the federally facilitated ACA Marketplace.
Because the metrics were aggregated across medical items and services, the data do not show which service categories — including home health services — had the highest prior authorization denial rates.
Prior authorization denials can impede the transition from hospital to home-based care settings. Medicare Advantage plans typically authorize initial home health visits and require additional approvals before patients obtain services — a process that can take more than a week, an expert previously told Home Health Care News. That waiting period can cause patients to forgo or pay out of pocket for home-based care, as well as disrupt care continuity or cause delays.
Dr. Mehmet Oz, administrator of the Centers for Medicare & Medicaid Services (CMS), has promoted efforts to digitize and streamline prior authorization requests, citing estimates that the process costs providers nearly $34,000 and 700 administrative hours per provider annually. In May, he instituted a Jan. 1, 2027, deadline for CMS-regulated payers to integrate electronic prior authorization interfaces.