Adverse influence of female gender on outcomes after coronary bypass surgery: a propensity matched analysis

Female patients have been shown to have a different risk profile and increased adverse events after coronary bypass grafting (CAB). The objective was to create a risk profile based on gender and look at outcomes in propensity matched groups with similar factors differing by gender. From May 2001 to December 2006, 976 patients underwent isolated CAB. Univariable analysis created a risk profile for female and male patients. Multivariable logistic regression was used to develop independent predictors of mortality. Propensity matching for the most predictive variables of adverse was used to create matched sets of 269 male and female patients to analyze outcomes independent of these variables. Of the 976 patients 31.7% were female. Of the 19 preoperative risk factors analyzed, diabetes, hypertension, older age, higher body mass index (BMI), African-American race were more predictive of female gender. Males had more smokers and acute myocardial infarction within seven days before surgery. Independent predictors of mortality were female gender (P=0.01), diabetes (P=0.02), increased age (P=0.02), acute MI <7 days (P=0.003). Propensity matching (for smoking, diabetes, hypertension, MI <7 days, age, BMI and race) still showed increased in-hospital complications and mortality for female patients. Female patients undergoing CAB have a different risk profile and have a higher incidence of adverse outcomes including death, which are not mitigated by careful matching with male patients.