Medicare Advantage Prior Authorization: Denial Rates and How to Appeal

Prior authorization — the requirement that a Medicare Advantage plan approve a service before it's delivered — is the operational reality that separates managed care from Original Medicare. In 2024, Medicare Advantage insurers processed nearly 53 million prior authorization determinations. Roughly 90% were approved. The remaining 4.1 million were denied.

Those 4.1 million denials are where families get hurt, and the denial rates for the services aging parents need most are far worse than the average.

Where Denial Rates Are Highest

The overall 7.7% denial rate obscures the concentration of denials in post-acute care — the transitions that happen when a parent leaves the hospital and needs rehabilitation or skilled nursing.

According to OIG data, Medicare Advantage plans deny prior authorization at dramatically higher rates for these transitions:

• Long-term care hospital (LTCH) admissions: 65% denial rate
• Inpatient rehabilitation facility (IRF) admissions: 54% denial rate
• Skilled nursing facility (SNF) stays: 95% of enrollees are subject to prior authorization, with denial rates for long-stay residents reaching 40% in some plans

These aren't abstract numbers. When a parent has a stroke or hip fracture and the hospital discharge planner determines they need inpatient rehab, a 54% denial rate means the odds of approval are roughly a coin flip. Under Original Medicare, the transfer happens when the doctor orders it — no prior authorization required.

The Hidden Cost: Delays

Even when prior authorization is ultimately approved, the review process introduces delays. Post-acute care authorization reviews average five to six days. During that time, the parent either remains hospitalized (exposed to hospital-acquired infections, occupying a bed) or is discharged home without the rehab services they need.

For a parent recovering from surgery who needs intensive daily physical therapy, a week of delay can meaningfully set back recovery.

How the Appeals Process Works

The saving grace in Medicare Advantage prior authorization is that appeals work. More than half of denied prior authorization requests are overturned when appealed. For denials processed by third-party contractors like naviHealth (which handles approximately half of skilled nursing facility prior-authorization requests), the overturn rate reaches 97%.

The problem: only 11.5% of denied requests are ever appealed. Most families either don't know they can appeal, don't understand the process, or can't manage the administrative burden during a medical crisis.

The five levels of Medicare Advantage appeals:

1. Plan reconsideration — the plan reviews its own denial. Must be filed within 65 days. The plan has 30 days to decide (72 hours for expedited requests involving active care).
2. Independent Review Entity (IRE) — if the plan upholds the denial, it automatically goes to an independent reviewer. The IRE has 30 days (72 hours expedited).
3. Office of Medicare Hearings and Appeals (OMHA) — an administrative law judge hearing. Must be filed within 60 days of the IRE decision. Requires a minimum amount in controversy ($200 in 2026).
4. Medicare Appeals Council — review of the ALJ decision.
5. Federal district court — judicial review for appeals meeting the $1,960 amount-in-controversy threshold (2026).

Most families never get past level 2. The critical action is filing the initial appeal quickly — especially for expedited reviews when a parent is actively in the hospital awaiting a transfer.

What Families Can Do

Ask the right question at the hospital. When a discharge planner tells you the plan denied a SNF transfer, ask: "Has the expedited appeal been filed?" Hospitals and attending physicians can — and should — file expedited reconsiderations on the patient's behalf.

Document medical necessity. The strongest appeals include the attending physician's clinical notes specifying exactly why the post-acute care is medically necessary. Generic language ("patient needs rehab") is weaker than specific documentation ("patient requires daily skilled physical therapy to restore ambulation following left hip arthroplasty; home discharge is clinically unsafe due to fall risk and inability to perform transfers independently").

Know the deadlines. Expedited appeals must be decided within 72 hours. If the plan doesn't respond in time, document the missed deadline and ask for escalation; a missed deadline is not an automatic approval.

Contact SHIP. Every state has a free State Health Insurance Assistance Program with counselors who can help navigate appeals at no cost.

The Comparison to Original Medicare

Under Original Medicare (with or without a Medigap policy), prior authorization applies to almost no services. The doctor orders care, Medicare pays its share, and the Medigap policy covers the remaining cost-sharing. There is no insurance company reviewing whether a hospitalization or rehab transfer is "medically necessary" before it happens.

This difference is the primary reason many families with aging, medically complex parents choose Original Medicare + Medigap despite its higher monthly premiums. The Medigap vs Medicare Advantage decision guide includes a prior authorization appeal workflow and cost-comparison framework for families weighing this trade-off.

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