April 18, 2000 -- HMO members who need heart bypass surgery are far more likely than other patients to have the operation done in a hospital where the death rate is higher than average, a new study finds. That's particularly true for those covered by a Medicare HMO, says a study published in the Journal of the American Medical Association.
While the research doesn't prove that HMOs are steering heart patients away from better or costlier care, researcher Lars Erickson, MD, MPH, tells WebMD that there's a "dramatic difference" between how HMO patients and so-called fee-for-service patients (those whose insurance pays for every procedure separately) are referred for treatment. Erickson is a pediatric cardiologist at Boston's Children's Hospital.
Erickson and colleagues analyzed the medical records of nearly 59,000 patients in New York state who underwent bypass surgery. New York, Erickson says, has done a "spectacular job" of collecting information on hospital death rates in an effort to show doctors and patients which institutions are doing the best job.
The hospitals were considered to have lower-than-average mortality rates if 2.1% or less of all patients admitted during the three-year study period died there; the rates were considered higher than average if 3.2% or more of the patients died.
HMO members were 23% less likely to get their heart operation at one of the hospitals with a lower-than-average death rate, Erickson says. For those in Medicare HMOs, the chance of getting into one of these hospitals was 39% less than for patients with fee-for-service insurance.
One possible explanation for the discrepancy is that HMOs may simply be getting a better deal from some hospitals to handle their bypass surgery patients. Other financial incentives may be at work; HMOs may give the primary care doctors who are responsible for managing patients' overall health care costs a price break for steering bypass patients to particular hospitals.
Dollar considerations may also have affected the Medicare HMO patients, who were virtually excluded from many of the low-death-rate hospitals surveyed. Hospitals that required patients to make a sizable copayment could be dropped from an HMO's list, Erickson says. He couldn't find any significant difference among the bypass patients or their doctors that would account for which hospitals the patients were sent to.