Traditional Medicare patients are less healthy than Medicare Advantage patients at end of life, a new analysis finds.

MA patients reported having better health and fewer memory problems than patients receiving coverage directly from the government, researchers at the University of Michigan Medical school said in a survey covering the last six months of life. Participants covered by private companies also reported being more independent.

Survey answers from 1998 to 2012 were examined in the analysis, accounting for more than 9,000 Medicare patients. Around 24% were MA enrollees.

The Centers for Medicare & Medicaid Services says nearly one-third of of the nation’s seniors are now receiving coverage through private companies, while the rest rely on government-funded care.

According to researchers, information from the study could serve as a vital tool for health policy decision-makers, who often fail to consider data from both parts of the Medicare program.

“If we’re going to have a national conversation on end-of-life care and the spending it drives, we shouldn’t only base it on data from two thirds of the elderly population,” said Elena Byhoff, M.D., M.S., who led the analysis. “Future research and policy decisions should be based on complete utilization data from both major parts of the Medicare program.”