HMO provider networks in Medicare+Choice: comparing Medicare and commercial lines of business.

The Medicare+Choice (M+C) program was intended to expand choice of managed care plans for Medicare beneficiaries. In the past few years, the opposite has occurred as many participating HMOs reduced Medicare service areas or withdrew from the program. This paper presents findings from a study of the provider networks of 85 HMOs that were participating in M+C in 1999. The study shows that provider networks serving Medicare enrollees are usually similar to those developed for HMOs' commercial line of business, but when they are different, Medicare provider networks are smaller. Most HMOs also had at least some problems maintaining their Medicare provider networks. These findings have implications for the future of the Medicare+Choice program and Medicare enrollees' access to health care.