Hospital readmission after coronary artery bypass grafting:: Are women doing worse?

Background. In studies of gender effects on outcome after coronary artery bypass grafting, early mortality has consistently tended to be higher among women, whereas long-term results have varied. The aim of this study was to identify predictors of hospital readmission and assess the effect of gender. Methods. Between 1987 and 1996, 7,493 patients were discharged alive after primary coronary artery bypass grafting and were followed up to the first readmission, date of death, or December 31, 1996. The hazard ratios for the risk factors found were used to calculate a readmission risk score. Results. A total of 4,780 (63.8%) patients were readmitted. The fraction not readmitted within 1, 5, and 10 years were 61%, 29%, and 14% (95% confidence intervals = 60 to 62, 28 to 30, and 12 to 16), respectively. The risk of readmission was highest early after operation and then gradually decreased. Older age, active smoking, diabetes, previous myocardial infarction, unstable angina, dyspnea, severe left ventricular dysfunction, advanced New York Heart Association functional class, bypass time of 2 hours or more, and length of stay all independently increased the risk of readmission. Female sex was a significant risk factor in univariate but not in multivariate analysis. In all age groups, women had a one unit higher risk score. Given the same risk score, the risk of readmission was similar between sexes. Conclusions. This study showed an acceptable risk of readmission after coronary artery bypass grafting. Women more often had risk factors related to readmission. However, given identical disease severity, the risk was similar in men and women.