Association of case volume with mortality of Chinese patients after coronary artery bypass grafting: Taiwan experience

Background: An inverse relationship between surgeon volume or hospital volume and mortality has been reported in Western countries, but seldom in Asia. Methods and Results: The data of 4,724 patients with coronary artery disease who underwent coronary artery bypass graft (CABG) surgery in Taiwan between 1^st January 2000 and 31^st December 2001 were analyzed in this prospective cohort study. Overall, 3.45% of patients died in-hospital (IH), and 6.48% patients died within 30 days after discharge (AD30); 85.0% of patients in the AD30 group died at home within 1 day of discharge because of a "cultural preference for dying at home". After adjustment by stepwise logistic regression for age, sex, cardiac function, co-morbidity and in-hospital complications, higher provider volume was still associated with lower mortality rates for CABG, especially higher surgeon volume. Because IH mortality can be affected by different culture, the IH plus AD30 mortality rate is more appropriate as a proxy to reflect the mortality of a specific procedure. Conclusions: The relationship of higher-volume hospitals or surgeons with lower mortality rate for patients undergoing CABG is a general phenomenon in Western and Chinese societies. However, the combination of the AD30 and IH mortality rates has to be considered when investigating procedural mortality rates in Chinese society.