Study Finds Drug Coverage Changes in Medicare Part D Plans

The number of both the standalone prescription drug plans (PDP) and the low-income subsidy (LIS) benchmark plans in Medicare Part D decreased between 2023 and 2024, according to a new review from Avalere.

Of the 801 prescription drug plans offered in 2023 across the United States, 95 were no longer offered in 2024, which is a decrease of 12%. Additionally, almost half of Medicare beneficiaries enrolled in the low-income benchmark plans were in plans that lost benchmark status, meaning enrollees had to choose a new plan or pay a premium in 2024.

Kylie Stengel

“We did see a reduction in the number of PDP offerings in general, but this is really a significant decrease in specifically the LIS benchmark plan offerings,” Kylie Stengel, associate principal at Avalere said in an interview. “We do believe that is due to the changing market conditions under the Inflation Reduction Act, although not all of the IRA changes are in effect as of yet. These changes together have changed how plans thought about their offerings for 2024.”

The Inflation Reduction Act’s $35 cap on insulin out-of-pocket costs went into effect in January 2023. Next year will see two important elements of the Inflation Reduction Act being implemented: a $2,000 cap on out-of-pocket costs under Part D and the Prescription Payment Plan, sometimes called the “smoothing” program, where beneficiaries with Medicare Part D drug coverage will have the option to pay out-of-pocket costs in monthly payments spread out over the year.

Medicare Part D provides prescription drug coverage to supplement traditional Medicare or Medicare Advantage plans. In 2023, more than 50 million of the 65 million Medicare beneficiaries were enrolled in Part D plans, according to KFF.

Seniors with low incomes are eligible for prescription drug coverage from plans that meet a certain benchmark for no additional premium costs. The benchmark is the maximum premium that the Medicare program will pay for drug plan coverage.

“The benchmark is an enrollment weighted average in each region,” Stengel said. “CMS takes the average of all bids from both PDP and Medicare Advantage plans and sets a premium amount by region.”

In its analysis, Avalere assessed data from the Part D Public Use Files for 2023 and 2024 from the Centers for Medicare and Medicaid Services. This data contains information about formulary, cost sharing, and utilization management for Medicare prescription drug plans.

Avalere researchers looked at coverage changes and focused on 24 of the most used, single-source branded drugs in five therapeutic categories: anticoagulants; asthma/chronic obstructive pulmonary disease (COPD) autoimmune; multiple sclerosis and pulmonary hypertension. Avalere, however, is not releasing the names of the drugs they analyzed.

Researchers conducted two sets of comparisons. In the prescription drug plans, they looked at. Changes in formularies from 2023 and 2024 and the differences for plans that exited the market. They also assessed the low-income benchmark plans for whether they maintained benchmark status and the differences in formularies in plans that lost and plans that maintained benchmark status.

“When you look under the hood, when you look at specific therapeutic areas and regions, there is a lot of variability,” Stengel said. “When you’re looking across all drugs at a national level, you might not see a lot of change.”

One of the biggest areas to see change was the coverage of drugs to treat patients with pulmonary hypertension. In 2023, 39% of plans covered the drugs for pulmonary hypertension. In 2024, just 30% of plans did.

Avalere also found regional differences in coverage for some therapeutic areas. For example, coverage of drugs to treat patients with multiple sclerosis was lower among plans that remained in the market in 2024 in 11 regions but higher in 13 regions.

Avalere found that cost-sharing changes were limited for autoimmune, multiple sclerosis, and pulmonary hypertension drugs. However, use of coinsurance for anticoagulants and drugs that treat patients with asthma/COPD increased substantially for all prescription drug plan comparisons.

For the low income subsidy benchmark plans, there were regional differences on the utilization management used for the anticoagulant drugs. In five regions, there was a 20-percentage-point or more difference in utilization management among plans that lost benchmark status compared with plans that maintained benchmark status.

“It’s hard to know what factors are driving this; we didn’t do an assessment in terms of why there might have been a decrease in coverage for some of these therapeutic areas. But pulmonary hypertension is an area with a lot of higher cost drugs so we thought might expect there to more changes,” Stengel said. “Plans might be reacting to the elimination of patient cost-sharing to reduce their financial risk.”

But she said it may be too early to predict plan offerings for 2025. “I think we can expect potentially there to be less enhanced plans in the market just because the overall the basic benefit is a richer compared with previous years.”