Five‐Year Hospital Readmission After Coronary Artery Bypass Surgery and the Association With Off‐Pump Surgery and Sex

Background Limited data exist on long-term readmission and its association with patient and procedural characteristics after coronary artery bypass grafting. We aimed to investigate 5-year readmission after coronary artery bypass grafting and specifically focus on the role of sex and off-pump surgery. Methods and Results We performed a post hoc analysis of the CORONARY (Coronary Artery Bypass Grafting [CABG] Off or On Pump Revascularization) trial, involving 4623 patients. The primary outcome was all-cause readmission, and the secondary outcome was cardiac readmission. Cox models were used to investigate the association of outcomes with sex and off-pump surgery. Hazard function for sex was studied over time using a flexible, fully parametric model, and time-segmented analyses were performed accordingly. Rho coefficient was calculated for the correlation between readmission and long-term mortality. Median follow-up was 4.4 years (interquartile range, 2.9-5.4 years). The cumulative incidence rates of all-cause and cardiac readmission were 29.4% and 8.2% at 5 years, respectively. Off-pump surgery was not associated with either all-cause or cardiac readmission. The hazard for all-cause readmission in women over time was constantly higher than the hazard for men (hazard ratio [HR], 1.21 [95% CI, 1.04-1.40]; P=0.011). Time-segmented analyses confirmed the higher risk for all-cause (HR, 1.21 [95% CI, 1.05-1.40]; P<0.001) and cardiac (HR, 1.26 [95% CI, 1.03-1.69]; P=0.033) readmission in women after the first 3 years of follow-up. All-cause readmission was strongly correlated with long-term all-cause mortality (Rho, 0.60 [95% CI, 0.48-0.66]), whereas cardiac readmission was strongly correlated with long-term cardiovascular mortality (Rho, 0.60 [95% CI, 0.13-0.86]). Conclusions Readmission rates are substantial at 5 years after coronary artery bypass grafting and are higher in women but not with off-pump surgery. Registration URL: http://www.clinicaltrials.gov/; Unique identifier: NCT00463294.