Enrollment in Medicare Advantage preferred provider organization plans increased to more than 400,000 in October, up 130% from the total recorded a year earlier.

Researchers at Mark Farah Associates, Kennebunk, Maine., have reported that finding in results from an analysis of data from the Centers for Medicare and Medicaid Services.

Total Medicare Advantage plan enrollment increased 15%, to 8.8 million, but health maintenance organization plans’ share of Medicare Advantage enrollment fell to about 65% of the total, from 74% of the total.

Private fee-for-service plans account for 19% of Medicare Advantage program enrollment, up from 11%, the researchers report.