5 Things to Know: New Insights on Prior Authorization for Medicare, Medicaid, ACA Plans

August 18, 2026

Insurers offering Affordable Care Act (ACA), Medicare Advantage, and Medicaid Managed Care plans must now provide data about prior authorization, denials, and response times.

New research from the Kaiser Family Foundation (KFF) evaluated data for 2025—the first year it is available—and identified trends across federal plan types. Here’s what you need to know:

1.  Denial rates vary across government health plans

For standard prior authorization requests, the overall denial rates across the various plan types range from 12 percent to 18 percent.

Standard denial rates were 12 percent for Medicare Advantage; 14 percent for Medicaid Managed Care; and 17 percent for ACA plans. Expedited requests for review had similar or slightly higher denial rates, the researchers noted. The analysis includes metrics for 14 insurers with 71 million enrollees across markets.

 2.  More than 40 percent of cases are overturned on appeal across the board

Successful appeals across Medicare, Medicaid, and the ACA also varied.

The percentage of successful requests approved after appeal: Medicare Advantage, 67 percent; Medicaid Managed Care, 47 percent; and the ACA marketplace, 43 percent.

“High overturn rates could raise questions about whether the initial request should have been approved or could indicate that the initial request was missing the required documentation to justify the service,” the researchers note. “Either way, the appeals process can be complicated and time-consuming for providers and patients.”

3.  Response times are consistent

The median response times for standard prior authorization requests were about one day across Medicare Advantage, Medicaid Managed Care, and ACA plans. Expedited requests ranged from 0.4 days (Medicare Advantage) to 0.9 days (ACA marketplace).

The researchers noted some of the time to respond varied among the larger insurers.

4. Unknowns are built into the data

The researchers noted uniform reporting requirements have helped understand the use of prior authorization in health care, but there is still room for understanding.

The total number of prior authorization requests would offer better understanding about whether denial rates are truly meaningful or are outliers due to low volume.

“Insurers are not required to report the number of prior authorization requests for each metric (only percentages), which limits the ability to make useful comparisons and gauge the scale of requests, denials, and approvals behind reported percentages,” the researchers wrote.

5. Streamlining prior authorization supports access to care

HAP continues to support hospitals and patients through common-sense policies and legislation that streamline prior authorization. This includes supporting legislation that would establish an electronic prior authorization process for Medicare Advantage plans.

Additional information about the KFF report is available online.