Objective: To assess changes in outcomes of coronary artery bypass graft (CABG) surgery in New York since 1989, when the State Department of Health began collecting, analyzing, and disseminating information regarding risk factors, mortality, and complications of CABG surgery. These new data stimulated specific quality improvement activities at hospitals throughout the state.
Design: A clinical database was used to identify significant independent risk factors and to assess risk-adjusted provider mortality rates.
Setting: All 30 hospitals performing CABG surgery in New York during the period 1989 through 1992.
Patients: All 57,187 patients undergoing isolated CABG surgery who were discharged from New York State hospitals in 1989 through 1992.
Main outcome measures: Actual, expected (from a logistic regression model), and risk-adjusted in-hospital mortality.
Results: Actual mortality decreased from 3.52% in 1989 to 2.78% in 1992. Because average patient severity of illness increased, risk-adjusted mortality decreased even more--a decrease of 41% from 4.17% in 1989 to 2.45% in 1992. The risk-adjustment model performed well; there were no clinically or statistically significant differences between actual and predicted numbers of deaths at any of 10 levels of patient severity.
Conclusions: We believe that this quality improvement program, based on the collection and dissemination of risk-adjusted mortality data for CABG surgery, played a significant role in the observed decline in the death rate from this procedure. Quality improvement programs based on similar principles for other procedures and conditions should be undertaken.