Insurance Denials for Brand-Name Drugs Surge 67% Over Six Years, JAMA Study Finds
Key Insights
A Johns Hopkins-led study analyzing over 2 million prescription attempts found insurance rejections for single-source brand-name drugs rose from 24.3% in 2018 to 40.7% in 2024, a 67% increase.
Nearly half (48.4%) of initially rejected prescriptions were not filled with the prescribed drug or a therapeutic alternative within 90 days, with patients who did obtain treatment waiting an average of 12 days.
GLP-1 receptor agonists (search) for weight loss had the highest rejection rate at 85%, while oral anticoagulants had the lowest at 6.7%, highlighting wide variation across therapeutic classes.
A new study published July 9 in JAMA reveals that insurance denials for first-time brand-name prescription fills have surged dramatically, with rejection rates climbing from 24.3% in 2018 to 40.7% in 2024—an increase of more than two-thirds. The research, led by investigators at the Johns Hopkins Bloomberg School of Public Health and the American Enterprise Institute (search), analyzed over 2 million prescription attempts for single-source brand-name drugs with no generic competitors across commercial insurance, Medicare, Medicaid, and Affordable Care Act marketplace plans.
"We found that insurance restrictions are increasingly shaping whether and when patients receive medications their clinicians prescribe," said Joseph Levy, PhD, assistant professor in the Bloomberg School's Department of Health Policy and Management and lead author of the study. "While these policies may help control drug spending, they can also create meaningful barriers to timely treatment and place growing administrative burdens on patients, pharmacists, and clinicians."
The Scope of Prescription Rejections
The study drew from IQVIA's Formulary Impact Analyzer, a national database of anonymized outpatient pharmacy claims representing all major U.S. insurance markets. Researchers examined pharmacy claims data from 1.17 million individuals attempting to fill prescriptions for single-source brand-name drugs for the first time between January 2018 and September 2024.
Among initially rejected fill attempts, 48.4% were not followed by a fill of the prescribed drug or another drug in the same therapeutic class within 90 days. For patients who eventually obtained treatment, prescriptions were filled on average 12 days after the initial rejection—a delay that could have clinical consequences depending on the condition being treated.
Of the prescriptions initially denied, 39% were ultimately filled with the originally prescribed medication within 90 days, while 13% were filled with a different drug in the same therapeutic class.
Utilization Management as the Primary Driver
Nearly one-third of initial fill attempts—32%—were rejected because of formulary exclusions or insurers' utilization management rules. These rules, designed to help control costs, often require prior authorization by the insurance company or mandate that patients try other drugs before receiving the originally prescribed brand-name medication.
The growing use of utilization management rules was identified as the greatest driver of brand-name prescription drug rejections. Commercial insurance plans and Medicaid managed care plans experienced some of the sharpest increases in utilization management restrictions during the study period.
Variation Across Therapeutic Classes and Insurance Types
Rejection rates varied substantially across therapeutic classes. Incretin-based therapies for weight loss—including GLP-1 receptor agonists (search) and related drugs—faced the highest initial rejection rate at 85%. These medications, such as Wegovy and Ozempic, were among the most common single-source branded drugs in the study. At the other end of the spectrum, oral anticoagulants had the lowest rejection rate at just 6.7%.
The study also found substantial variation across insurance types. Marketplace exchange plans and Medicaid managed care plans experienced the highest rejection rates, with nearly half of all initial prescription attempts denied. Medicare plans had comparatively lower rejection rates.
The Financial Context
Brand-name drugs account for a small fraction of total prescriptions but the majority of U.S. drug spending. According to the Association for Accessible Medicines, brand-name drugs represented about 10% of total prescriptions filled and 88% of spending in 2024—approximately 435 million brand-name prescriptions costing $700 billion. In contrast, generics and biosimilars accounted for about 90% of prescriptions filled and 12% of prescription drug spending, or roughly 3.9 billion prescriptions costing $98 billion.
Implications for Clinical Practice and Policy
Because coverage barriers were identified at the pharmacy counter, the study captures what happens after a prescription is written, not whether formularies influence clinicians' initial prescribing decisions. The findings suggest that clinicians may not always know when a prescribed medication is excluded from a patient's formulary or requires prior authorization before it can be filled.
The researchers note that better real-time information about insurance restrictions at the point of prescribing, along with simpler prior authorization processes, could help reduce delays in care. "As utilization management becomes more common, it's important to better understand how these policies affect real-world treatment initiation and patient's access to medicines," Levy said.
The authors suggest that simplifying and standardizing prior authorization requirements could reduce avoidable pharmacy rejections and treatment delays. However, they acknowledge that such reforms may involve trade-offs, including higher drug costs, as formulary management tools can help insurers negotiate discounts, encourage the use of preferred or evidence-based therapies, and promote more clinically appropriate and cost-effective prescribing.
Study Limitations
The analysis has several limitations. The database includes claims only from participating pharmacies, meaning prescriptions filled elsewhere or through other payment channels may be missed. The researchers also could not always identify rejection reasons or determine whether patients received clinically appropriate alternatives from another therapeutic class.
The research was supported by Arnold Ventures. Levy and co-lead author Benedic Ippolito, a senior fellow at the American Enterprise Institute (search), were supported by the Johns Hopkins University-American Enterprise Institute Fellowship Exchange Program. The study, "Formulary-Related Insurance Denials of Single-Source Branded Drugs in the United States," was co-authored by Joseph F. Levy, G. Caleb Alexander, Boris Vabson, and Benedic N. Ippolito.