The relationship between managed care insurance and use of lower-mortality hospitals for CABG surgery

Context  Explicit information about the quality of coronary artery bypass graft (CABG) surgery has been available for nearly a decade in New York State; however, the extent to which managed care insurance plans direct enrollees to the lowest-mortality CABG surgery hospitals remains unknown. Objective  To compare the proportion of patients with managed care insurance and fee-for-service (FFS) insurance who undergo CABG surgery at lower-mortality hospitals. Design  A retrospective cohort study of CABG surgery discharges from 1993 to 1996, using New York Department of Health databases and multivariate analysis to estimate the use of lower-mortality hospitals by patients with different types of health insurance. Setting  Cardiac surgical centers in New York, of which 14 were classified as lower-mortality hospitals (mean rate, 2.1%) and 17 were classified as higher-mortality hospitals (mean rate, 3.2%). Patients  A total of 58,902 adults older than 17 years who were hospitalized for CABG surgery. Patients were excluded if their CABG surgery was combined with any valve procedure or left ventricular aneurysm resection or if they were younger than 65 years and enrolled in Medicare FFS or Medicare managed care. Main Outcome Measure  Probability of a patient receiving CABG surgery at a lower-mortality hospital. Results  Compared with patients with private FFS insurance (n=18,905), patients with private managed care insurance (n=7169) and Medicare managed care insurance (n=880) were less likely to receive CABG surgery at a lower-mortality hospital (relative risk [RR] of surgery at a lower-mortality hospital compared with patients with private FFS insurance, 0.77; 95% confidence interval [CI], 0.74-0.81; P<.001; and RR, 0.61; 95% CI, 0.54-0.70; P<.001, respectively, after controlling for multiple potential confounding factors). Patients with Medicare FFS insurance used lower-mortality hospitals at rates more similar to those with private FFS insurance (n=31,948; RR, 0.95; 95% CI, 0.91-0.98; P=.004). Conclusions  Patients in New York State with private managed care and Medicare managed care insurance were significantly less likely to use lower-mortality hospitals for CABG surgery compared with patients with private FFS insurance.