Study examines impact of managed care on stroke prevention surgery

December 29, 2008

Policymakers and economists often promote managed-care plans based on the assumption that they prevent the overuse of unnecessary surgical procedures or help steer patients to high-quality providers, compared to traditional fee-for-service insurance plans. A recent study by a researcher at UT Southwestern Medical Center, however, found that in the case of one common surgical procedure, the checks and balances assumed with managed care did not improve the quality or outcome of care.

The study, published in the December issue of the American Journal of Medical Quality, examined differences in care for Medicare patients who received a carotid endarterectomy (CEA) and were enrolled in either managed-care or fee-for-service plans. In managed-care, an insurance company often acts as an intermediary between a person seeking care and the physician. A fee-for-service plan allows a person to make all health care decisions independently.

CEA is a surgical procedure to remove blockages in the neck arteries that can lead to strokes. National guidelines exist that establish the circumstances under which CEAs are likely to produce benefits for patients, and the procedure is nearly always performed electively.

Dr. Ethan Halm, chief of the William T. and Gay F. Solomon Division of General Internal Medicine at UT Southwestern and the study's lead author, used data from the New York Carotid Artery Surgery study for his current investigation. The data - with statistics on a patient pool of more than 11,400 cases - includes information on all Medicare beneficiaries who underwent a CEA between January 1989 and June 1999 in New York State.

"This is the first study to look at the impact of managed-care on a broad spectrum of quality measures after a common and costly surgical procedure," said Dr. Halm, who leads the new Division of Outcomes and Health Services Research in the Department of Clinical Sciences. "Managed-care plans have financial and quality-of-care incentives to prevent overuse of unnecessary procedures and steer their beneficiaries to high-quality providers. Our study shows that in the case of carotid endarterectomy, managed-care plans failed to deliver on this promise. The plan did not have a positive impact on inappropriateness, referral patterns or patient outcomes."

The study, completed while Dr. Halm was a faculty member at Mount Sinai School of Medicine in New York, found there was no difference in rates of inappropriate surgery between managed-care or fee-for-service plans.

"There was also no difference in risk-adjusted rates of death or stroke between the plans," said Dr. Halm.

In addition, managed-care patients were less likely to have their procedure performed by a high-volume surgeon or hospital.

"Overuse of CEA is potentially a good tracer for evaluating the effectiveness with which managed-care might influence health care quality," Dr. Halm said. "Whether the findings of this study reflect the fact that the Medicare managed-care plans tried to exert such influence but failed or did not try at all is a worthy subject for future research."

Source: UT Southwestern Medical Center