EFFECT OF AGE ON MORTALITY IN CORONARY-ARTERY BYPASS-SURGERY IN NEW-YORK, 1991-1992

The purpose of this study was to determine the effect of age on the in-hospital mortality of all 30,972 patients undergoing coronary artery bypass graft (CABG) surgery in New York in 1991 and 1992. Mortality rates were relatively low for patients 40-49, 50-59, and 60-64, 65-69, and 70-74 years old (1.10%, 1.65%, 2.17%, 2.76%, and 3.36%, respectively). However, CABG surgery mortality increased rapidly for patients 75 to 79 years old (5.28%) and patients greater than or equal to 80 years old (8.31%). To examine the independent effect of age on mortality after accounting for the effects of other significant risk factors, a multivariate statistical model was developed to identify the significant independent predictors of mortality. Age emerged as 1 of 24 significant predictors, with age greater than or equal to 75 demonstrating much higher mortality risk than lesser age. For example, the odds of an 80-year-old patient's dying in the hospital were 3.25 times the odds of a 50-year-old patient's dying in the hospital, assuming all other significant risk factors were identical.