Association between the Electronic Frailty Index and Length of Stay after Coronary Artery Bypass Grafting in Older Adults : A Retrospective Cohort Study Using Secondary Data

Purpose : This study examined the association between preoperative frailty and postoperative length of stay among older adults undergoing coronary artery bypass graft surgery.Methods : This retrospective study analyzed data obtained from older adults who underwent cardiac surgery at a tertiary hospital between January 2013 and December 2022. The final sample included 171 patients who underwent isolated coronary artery bypass graft surgery. Participants were classified as non-frail, pre-frail, or frail using the electronic Frailty Index. Primary outcomes were intensive care unit (ICU) length of stay and total hospital length of stay, and secondary outcomes included postoperative complications. Group differences were compared, and generalized linear models with a gamma distribution and a log-link function were used to evaluate factors associated with length of stay.Results : Among the participants, 73.1% were classified as pre-frail or frail. The frail group had significantly longer ICU and hospital lengths of stay than the non-frail and pre-frail group, and postoperative complications were more frequent in the frail group. After adjustment for age, sex, Charlson Comorbidity Index, left ventricular ejection fraction, and admission route, the frail group had a longer ICU length of stay (exp(B)=2.76, 95% CI=1.83–4.17, <i>p</i> ＜.001) and hospital length of stay (exp(B)=1.87, 95% CI=1.37–2.55, <i>p</i> ＜.001) than the non-frail group.Conclusion : Preoperative frailty was associated with longer ICU and hospital stays among older adults undergoing coronary artery bypass graft surgery. Routine assessment using the electronic Frailty Index may help identify patients at risk for prolonged hospitalization and inform perioperative care planning.