Enrollment in the health alliance plan HMO is not an independent risk factor for coronary artery bypass graft surgery

Background: Henry Ford Hospital is the sole provider of cardiac surgical services for the Health Alliance Plan, a health maintenance organization (HMO) that presently serves 450 000 enrollees. Methods and Results: To determine the effect of managed care referral patterns on the outcome of coronary artery bypass graft (CABG) surgery, we retrospectively reviewed two concurrent groups of patients, 569 HMO patients and 225 patients with fee- for-service (FFS) insurance, who had undergone isolated primary CABG surgery between January 1, 1990 and January 31, 1994. The 605 patients with Medicare operated on during the same time frame were excluded to obviate age bias. Age, sex, use of cardiac medications, history of prior percutaneous transluminal coronary angioplasty or thrombolytic therapy, history of recent and remote myocardial infarction, extent of coronary disease, presence of preexisting comorbid conditions, and incidence of unstable clinical syndromes and left ventricular dysfunction (ejection fraction<40%) were comparable for both groups. Inhospital mortality (HMO group, 1.9%; FFS group, 2.2%), mean ICU stay (HMO, 2.6±0.3 days; FFS, 2.3±0.3 days), and total hospital length of stay (HMO, 9.8±0.8 days; FFS, 8.6±0.6 days) were likewise similar. Conclusions: These data refute the notion that the gatekeeper mentality often associated with managed-care health insurance vehicles results in delayed referral of patients with coronary artery disease and results in suboptimal outcome.