Huge Rates of Insurance Denials Get Overturned by Independent Review Experts

Persistence in appealing denied health insurance claims resulted in overturned decisions between 30% and 78% percent of the time, when the case reached independent review organizations (IROs), an analysis of completed external appeals showed.

Among 51,394 closed cases in New York state from May 31, 2019 to Dec. 10, 2025, almost half (46.7%) of external appeals were overturned at this third level of appeal, which often involves independent physicians and other specialists, Joseph Dov Bruch, PhD, of the University of Chicago, and colleagues reported in a research letter in JAMA Internal Medicine.

For example, of 6,469 denied home health care services claims that were appealed, 78.4% were overturned when clinical experts not affiliated with the insurance company examined the rationale. More than half of surgical services, dental or orthodontic procedures, and pharmacy or prescription drug denials were overturned by the IRO, the researchers found.

When analyzed by diagnosis, denied care for substance abuse treatments or mental health services was overturned 61.5% and 60.6% of the time, respectively. Central nervous system or neuromuscular disorder denials were overturned 53.1% of the time, and endocrine, metabolic, and nutritional denials were overturned 52.1% of the time. Cancer denials were overturned 45.1% of the time, they reported.

The analysis also tabulated IRO overturn rates by specific named health plan or insurance company. It found that Centers Plan for Healthy Living denials were overturned at the IRO level 85% of the time, while 51.1% of Aetna denials, 50% of Excellus denials, 49.8% of CVS Caremark denials, 48.3% of Fidelis Care denials, and 43.1% of Anthem Blue Cross Blue Shield denials were reversed.

“We show across the board that the external appeal overturn rate is quite high, but that there definitely is a distribution,” Bruch told MedPage Today. “The biggest takeaway … is that consumers have a major opportunity to pursue these types of independent reviews after they exhaust the internal review.”

The researchers said they assumed that reversal of the denial was the appropriate decision and the denial was incorrect. “It’s possible more information is provided” during the IRO review, Bruch said. It’s also possible that health plan reviewers may be “more discriminatory toward certain types of settings or diagnoses” or treatment protocols they don’t approve, he added.

Examination by third-party physicians and other clinicians may change the decision, study co-author Ayesha Rahim, MA, of Brown University, told MedPage Today.

“Since the independent clinician is ultimately making the external appeal decision, we can reasonably assume they are influential in that sense,” she said. “However, whether their involvement can be shown to influence outcomes in a measurable way, such as higher overturn rates, is not something we were able to assess.”

Overturn rates could also be the result of the types of cases that get to that level of appeal, she said. “Without a comparison group, we cannot distinguish between these [and other] explanations.”

The report also showed that 47.1% of denials on the basis of medical necessity, 44% of denials based on care determined to be experimental or investigational, and 42.9% of formulary denials were overturned.

The researchers said they only looked at overturned claims in New York because the state data includes names of specific insurance companies, whereas other states may have the same data but aren’t as granular.

Bruch and colleagues also found that rates of overturned decisions increased over time, from 38% in 2019 to 52.5% in 2025. Annual appeal volume also increased during this period, from 4,128 in 2019 to 9,805 in 2025.

In New York, the IRO appeal level is usually the third level of appeal, which can come after a long, frustrating and bureaucratic process that often involves the patients, their physicians, and other caregivers writing letter after letter. After the insurance plan or company issues an initial review and denies the care, the decision can be appealed to a second level, an internal appeal review, which also is conducted by the insurance company.

If that is denied, the claim goes to the IRO, which can overturn the denial either in whole or in part. By New York state law, there are three certified IROs that conduct external reviews. They include board certified physicians and other providers.

Detailed data like that provided in the analysis can be “leveraged by regulators to identify specific health services, populations, or plans with denial practices that warrant closer scrutiny,” the researchers wrote. They acknowledged that denials can result from a variety of issues, such as human or technical errors, outdated claims systems, ambiguity in coverage rules. But it can also result from “inappropriate insurer behavior — and thus require different remedies.”

Asked if insurers who continually issue denials that are overturned should face penalties, Bruch replied: “Personally, I would be in favor of that, but potentially [there should also be] incentives for those with lower rates.” But how such incentives would be implemented, he said, would have to be carefully thought through.

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