First-time prescription rejections rose 67% between 2018 and 2024, with nearly half of denied patients receiving no comparable medication within 90 days.

A new study published in JAMA puts hard numbers behind something patients and doctors have been telling me for years: getting a prescription filled increasingly means running an obstacle course of denials, prior authorization forms, and step therapy requirements — and a lot of people never make it through.

Researchers from Johns Hopkins Bloomberg School of Public Health and the American Enterprise Institute analyzed more than 2 million first-time attempts to fill prescriptions for brand-name drugs that have no generic alternative, using pharmacy claims data covering nearly every major insurance market in the country: commercial plans, Medicare, Medicare Advantage, Medicaid, and ACA marketplace plans. The data ran from January 2018 through September 2024.

Here’s what they found:

• Rejections are way up. In 2018, insurers turned down 24.3% of first-time fill attempts for these drugs. By 2024, that had jumped to 40.7% — a 67% increase.
• Coverage rules are the driver. Overall, 32% of initial attempts were rejected: 14.8% because the drug was excluded from the formulary outright, and 17.2% because it required prior authorization or step therapy — insurer-speak for “try something cheaper first.”
• Nearly half of rejected patients got nothing. Of everyone who was turned down, only 38.6% eventually got the original drug within 90 days, and 13% got a different drug in the same class. But 48.4% — essentially half — received no medication in that class at all within three months.
• Delays add up. Even patients who eventually got their medicine waited an average of 12.2 days after the initial rejection.
• Where you get your coverage matters enormously. Rejection rates were highest in ACA marketplace plans (48.7%) and Medicaid managed care (49.8%) — nearly one in two prescriptions. Traditional Medicare drug plans (24.0%) and Medicare Advantage (19.8%) had noticeably lower rejection rates.

Why this matters

The insurance industry has a ready answer for all of this: prior authorization and step therapy exist to control costs and steer patients toward drugs with the best evidence behind them, not just the most expensive ones. There’s some truth in that — utilization management can reduce unnecessary spending and has, in some cases, nudged prescribing toward cheaper, equally effective alternatives.

But this study makes clear that the tradeoff is not small or hypothetical. When nearly half the people who get turned down simply never receive treatment in that drug class — not “later,” not “with a substitute,” but never, at least within 90 days — that’s not utilization management working as intended but as a barrier that outright blocks care for a huge share of patients, many of whom presumably still need what their doctor originally prescribed.

The study lands in the middle of a real fight over these practices. Federal regulators have been pushing to speed up and standardize prior authorization. Several states have passed laws limiting insurer review times, exempting doctors with track records of low rejection rates from prior authorization requirements altogether, or requiring plans to honor authorizations a patient already has when they switch coverage.

Insurers will point out that some of the increase in rejections reflects more brand-name drugs entering the market during the study period. But that doesn’t explain away the core finding: patients across every type of coverage are hitting more roadblocks, and for close to half of them, the medicine their doctor decided they needed simply never arrives.