Blog: Three companies cover half of Medicare Part D members

When the CMS dropped data on Medicare's Part D prescription drug program last month, much of the focus centered on how much the government pays for specific drugs and which physicians are high prescribers. Lost in the shuffle is how the drug program is actually administered.

The CMS works with private health insurers and pharmacy benefits managers to offer Part D plans to Medicare members. Some are built into Medicare Advantage plans, while many others are stand-alone policies. More than 39 million people with a Part D plan this year, according to the latest CMS numbers.

Part D enrollment is heavily concentrated among a few large companies, according to an analysis of Part D plans by consulting firm Avalere Health. UnitedHealth Group, Humana and CVS Health Corp. together cover Medicare drug benefits for 19.7 million people, or more than half of all Part D subscribers. UnitedHealth and Humana also are the two most dominant Medicare Advantage insurers.

The eight largest Part D companies—which also include Express Scripts Holding Co., Aetna, Cigna Corp., WellCare Health Plans and Kaiser Permanente—cover about 75% of the market.

The average Part D premium for Medicare beneficiaries is $33.13, and out-of-pocket costs vary due to the program's coverage gap, called the “doughnut hole.” The Affordable Care Act will close that coverage gap by 2020.