The improving outcomes of coronary artery bypass graft surgery in Ontario, 1981 to 1995.

BACKGROUND

There is continuing uncertainty over the relative contribution of outcomes monitoring to changes in surgical outcomes over time. The authors studied temporal trends in the clinical characteristics and short-term outcomes of patients who underwent coronary artery bypass grafting (CABG) in Ontario before and after the implementation, in 1993, of a province-wide program to provide feedback on cardiac surgery outcomes.

METHODS

The authors analysed data from hospital discharge abstracts on the clinical characteristics and in-hospital death rates of all 67,784 patients who underwent isolated CABG in Ontario between Apr. 1, 1981, and Mar. 31, 1996.

RESULTS

Death rates were relatively stable during the first half of the 1980s, then declined gradually in the second half of the decade; this decline continued into the first half of the 1990s. In the 1990s patients were older than those in the 1980s, and a higher proportion had coexisting diseases. Between 1986/87 and 1995/96 the unadjusted death rate decreased by 52% (5.0% v. 2.4%) (p < 0.001). The annual relative rate of decline was approximately 6% (95% confidence interval 5% to 7%) in the period before the outcomes feedback program was implemented and about 9% (95% confidence interval 7% to 11%) in the period after implementation.

INTERPRETATION

Rates of death after CABG have been declining steadily in Ontario since the mid-1980s. Outcomes-based quality improvement interventions may facilitate; but are not a prerequisite for, improvements in the quality of surgical care.