Impact of Day of the Week of CABG on Hospital Length of Stay and Readmission Rates

Purpose We evaluated whether the weekday of surgery was associated with postoperative length of stay (LOS) or 30‐day readmission after elective and urgent isolated coronary artery bypass grafting (CABG) and identified patient‐ and procedure‐level predictors. Methods Elective and urgent isolated CABGs performed at Loma Linda University Medical Center and AdventHealth Cardiovascular Institute from 1/1/2014 to 12/31/2024 were retrospectively reviewed. LOS was compared across weekdays using one‐way ANOVA, and readmission rates were compared using Chi‐square testing. Predictors of LOS were evaluated using a generalized linear model with gamma distribution and log link, with exponentiated coefficients reported as LOS ratios. Predictors of readmission were assessed using multivariable logistic regression. Covariates were selected a priori and entered simultaneously. Results There was no difference in LOS by day among 8543 isolated CABGs ( p = 0.241). Age increased LOS by 0.8% per year ( p < 0.001), and BMI increased LOS by 0.4% per unit ( p = 0.001). Renal failure increased LOS by 92%, diabetes by 11%, and each additional graft by 4%; male sex decreased LOS by 8% (all p < 0.001). Treatment at Site 2 was associated with a 44% longer LOS ( p < 0.001).For readmission, increasing age ( p = 0.004) and diabetes ( p < 0.001) increased odds, whereas male sex was protective ( p < 0.001). Site 2 was associated with higher odds of readmission ( p = 0.039). Although the weekday of surgery was associated with readmission in unadjusted analysis, the association was not significant after adjustment. Conclusion LOS and readmissions after CABG hinge on comorbid burden and institutional practices, not surgical timing.