By Jordan Rau, Kaiser Health News

New research finds that many seniors who switch from their HMO-style Medicare Advantage plan to traditional Medicare have higher levels of significant health problems, fueling concerns that the private plans cater to more profitable, healthy beneficiaries but don’t provide the most attractive care for the very ill.
More than 13 million people, a quarter of all Medicare beneficiaries, are enrolled in these private plans. Enrollment has been growing, in part because the plans often offer lower premiums than does traditional Medicare, as well as special perks such as free gym memberships. Many Republicans want to build on them while capping the amount of money each Medicare beneficiary gets toward insurance. Democrats are disturbed the plans are more expensive than traditional Medicare and cut payments in the 2010 health law.
The federal government pays the plans a set fee for each enrollee. That has drawn concerns from some senior advocates that the plans have incentives to skim off the lowest-maintenance customers and leave the expensive patients to traditional Medicare.
A study released Thursday, by Gerald Riley, a researcher at the Centers for Medicare & Medicaid Services (CMS), adds to those concerns. The study looked at more than 240,000 people who dropped out of Medicare Advantage plans in 2007, and compared them with beneficiaries who remained in traditional Medicare the entire time. In the six months after leaving the private plans, the former Medicare Advantage patients used an average of $1,021 in medical services each month, while the patients in the control group cost Medicare $710 a month, the study found.