Mortality in Medicare Beneficiaries Following Coronary Artery Bypass Graft Surgery in States With and Without Certificate of Need Regulation

CONTEXT: Certificate of need regulation was designed to control health care costs by preventing health care facilities from expanding unnecessarily. While there have been several studies investigating whether these regulations have affected health care investment, few have evaluated the relationship between certificate of need regulation and quality of care. OBJECTIVE: To compare risk-adjusted mortality and hospital volumes for coronary artery bypass graft (CABG) surgery in states with and without certificate of need regulation. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of 911 407 Medicare beneficiaries aged 65 years or older, who underwent CABG surgery between 1994 and 1999 in 1063 US hospitals. MAIN OUTCOME MEASURES: States (and the District of Columbia) with continuous (n = 27), none (n = 18), or intermittent (n = 6) certificate of need regulation; mortality (in-hospital or within 30 days of CABG surgery) rates; and mean annual hospital volumes for CABG surgery. RESULTS: Unadjusted mortality was 5.1% in states without certificate of need regulation compared with 4.4% in states with continuous regulation, and 4.3% in states with intermittent certificate of need regulation (P<.001 for each comparison). Adjusting for demographic and clinical factors, mortality remained higher in states without certificate of need regulation compared with states with continuous certificate of need regulation (odds ratio OR, 1.22; 95% confidence interval CI, 1.15-1.28; P<.001). Using the same groups for comparison, the mean annual hospital volume for CABG surgery was 84% lower in states without certificate of need regulation (104 vs 191; P<.001) and more patients underwent CABG surgery in low-volume hospitals (<100 procedures annually) (30% vs 10% for states with continuous certificate of need programs; P<.001). Following the repeal of certificate of need regulation in states categorized as intermittent, the percentage of patients undergoing CABG surgery in low-volume hospitals tripled. CONCLUSIONS: Mortality rates for Medicare patients undergoing CABG surgery were higher in states without certificate of need regulation. Repeal of certificate of need regulations during the study period was associated with declines in hospital volume for CABG surgery.