Researchers found that patients who have traditional Medicare insurance are more likely to be sick and frail compared with patients who have Medicare Advantage.

An assumption that these 2 groups are the same could skew efforts to improve care and informed spending during end of life care, which accounts for one-quarter of Medicare spending, according to a study published in JAMA Internal Medicine.

The researchers gathered data from the Health and Retirement Study to track the health and other characteristics of older Americans. A representative sample of 9385 Medicare beneficiaries who died between 1998 and 2012 were included, with approximately 24% of these patients covered by Medicare Advantage.

Researchers found that Medicare Advantage beneficiaries were younger and healthier than traditional Medicare beneficiaries. Medicare Advantage beneficiaries were also more likely to be black, live in cities, and not as likely to qualify for Medicaid, according to the study.

Medicare Advantage beneficiaries were found to have better health, fewer problems with day-to-day tasks, and fewer memory and thinking problems compared with traditional Medicare beneficiaries. Researchers said that health policy decisions are mostly made by looking at traditional Medicare data since it is easy to access information about the cost and level of care for beneficiaries.

Since enrollment in Medicare Advantage has tripled in the past 12 years, beneficiaries should now be considered as well, according to the study.

"Potentially, we're overestimating the severity of illness in studies of Medicare end-of-life care, and evaluations of policy options," said lead researcher Elena Byhoff, MD, MS.

Other studies suggest that end-of-life care is not as expensive for patients with Medicare Advantage, but the current study indicates that who is enrolled is more significant.

"Medicare Advantage can limit patient options to providers and hospitals within a defined network," said Dr Byhoff. "Patients in Medicare Advantage plans are also known to be more likely to use hospice at the end of life, perhaps because awareness of that benefit is higher."

Researchers conclude that future Medicare decisions should include patients enrolled in Medicare Advantage.

"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," Dr Byhoff said. "Future research and policy decisions should be based on complete utilization data from both major parts of the Medicare program."