A recent Medicare Advantage enrollment boom is largely due to employers using the program to cover their retirees, researchers report.

Employers are increasingly using Medicare Advantage private fee-for-service plans as an option for offering retiree health benefits, according to the authors of a report released by the Henry J. Kaiser Family Foundation, Menlo Park, Calif.

Employers can contract with private FFS plans to provide Medicare and supplemental benefits to Medicare-eligible retirees.

Between 2006 and 2008, the number of Medicare beneficiaries enrolled in Medicare Advantage group plans increased to 1.7 million, from 900,000, according to analysts at Avalere Health, Washington, who looked at private FFS enrollment for Kaiser.

Most of the growth came from growth in employer private FFS contracts, the analysts write.

Prospects for continued enrollment growth in the group private FFS market are uncertain because of changes in Medicare Advantage payments and a recently enacted bill that will require private FFS plans to create provider networks by 2011, the analysts write.