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

Q: What are the key findings of this study?

Preoperative frailty (eFI ≥0.25) was associated with a 2.76-fold longer ICU stay (95% CI 1.83–4.17, p<0.001) and 1.87-fold longer hospital stay (p<0.001) after isolated CABG compared to non-frailty.

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Coronary artery disease undergoing isolated coronary artery bypass graft surgery (n=171). Intervention: Preoperative frailty (electronic Frailty Index ≥0.25) vs. Non-frail status (electronic Frailty Index 0-0.12). Primary outcome: Intensive care unit (ICU) length of stay (days) (exp(B) 2.76, 95% CI 1.83-4.17, p=<0.001).

Q: What does this research mean for the field?

Preoperative frailty assessed by the electronic Frailty Index is independently associated with significantly longer ICU and hospital lengths of stay following isolated coronary artery bypass graft surgery in older adults. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To examine the association between preoperative frailty assessed via the electronic Frailty Index and postoperative length of stay among older adults undergoing coronary artery bypass graft surgery.

Jung-Wook Shin

doi:10.34250/jkccn.2026.19.3.97

October 27, 2026Journal of Korean Critical Care NursingOpen Access

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

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Key result

Preoperative frailty linked to ~2.8-fold longer ICU stay after isolated CABG.

exp(B) 2.76
95% CI 1.83-4.17
P<0.001
n=171

Why the study?

This study was conducted to examine the association between preoperative frailty, assessed via the electronic Frailty Index, and postoperative length of stay among older adults undergoing coronary artery bypass graft surgery.

Is preoperative frailty assessed by the electronic Frailty Index associated with prolonged ICU and hospital length of stay in older adults undergoing isolated coronary artery bypass graft surgery?

Key Points

To examine the association between preoperative frailty assessed via the electronic Frailty Index and postoperative length of stay among older adults undergoing coronary artery bypass graft surgery.
Retrospective cohort analysis of 171 older adults who underwent isolated coronary artery bypass graft surgery at a tertiary hospital between January 2013 and December 2022.
Patients were classified as non-frail, pre-frail, or frail using a 36-deficit electronic Frailty Index calculated from electronic medical records.
Generalized linear models with a gamma distribution and log-link function assessed ICU and total hospital length of stay, adjusting for age, sex, Charlson Comorbidity Index, left ventricular ejection fraction, and admission route.
Overall, 73.1% of participants were classified as pre-frail or frail, and postoperative complications were more frequent in the frail group.
After multivariable adjustment, the frail group had a significantly longer ICU length of stay than the non-frail group (exp(B)=2.76, 95% CI=1.83–4.17, p < .001).
Adjusted total hospital length of stay was also significantly longer in the frail group compared to the non-frail group (exp(B)=1.87, 95% CI=1.37–2.55, p < .001).

Study Design

Type

Cohort (n=171)

Multicenter

No

Structured PICO

Is preoperative frailty assessed by the electronic Frailty Index associated with prolonged ICU and hospital length of stay in older adults undergoing isolated coronary artery bypass graft surgery?

P

Population

171 older adults (mean age 70.51 years, 26.3% female) undergoing isolated coronary artery bypass graft surgery at a single tertiary hospital in South Korea, followed until hospital discharge.

E

Exposure

Preoperative frailty classification using the electronic Frailty Index (eFI) into pre-frail (eFI 0.13–0.24, n=85, 49.7%) and frail (eFI ≥0.25, n=40, 23.4%) groups.

C

Comparator

Non-frail group (eFI 0–0.12, n=46, 26.9%) undergoing isolated CABG.

O

Outcome

Intensive care unit (ICU) length of stay (days from postoperative ICU admission to ICU discharge) and total hospital length of stay (days from surgery to final hospital discharge).

Main Result

Effect estimate: exp(B) 2.76 (95% CI 1.83-4.17)

Absolute Event Rate: 2% vs 1%

p-value: p=<0.001

Preoperative frailty assessed via an electronic health record-based frailty index (eFI) independently predicts prolonged ICU and hospital length of stay and higher pulmonary complications in older adults undergoing isolated CABG.

Limitations

Single-center, single-surgeon retrospective secondary data analysis limiting generalizability
10-year study period (2013-2022) during which surgical techniques and perioperative care may have changed
Exclusion of patients who died in-hospital in the primary dataset introduces potential selection and survivor bias
Potential underreporting of health deficits in electronic medical records and inclusion of patients aged 60-64 years without specific local validation
Residual confounding due to lack of data on coronary artery disease severity and specific intraoperative characteristics
Single-center, single-surgeon retrospective secondary data analysis limiting generalizability and spanning 10 years during which clinical practices may have changed
Selection bias and survivor bias due to the exclusion of patients with in-hospital mortality in the primary dataset
Potential omission of deficits in electronic medical records used for eFI calculation and inclusion of patients aged 60–64 years (younger than the original eFI validation cohort of ≥65 years)
Residual confounding due to lack of data on coronary artery disease severity and detailed surgical characteristics
Potential underestimation of postoperative complication rates due to reliance on retrospectively verifiable records

Ask about this paper

Answers are grounded in this paper and cite their sources.

Implication

May inform preoperative planning in older CABG patients; extends eFI associations but leaves open whether frailty interventions shorten stays.

Abstract

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, p ＜.001) and hospital length of stay (exp(B)=1.87, 95% CI=1.37–2.55, p ＜.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.

Discussion

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Cite This Study

Jung-Wook Shin (2026) conducted a cohort in Coronary artery disease undergoing isolated coronary artery bypass graft surgery (n=171). Preoperative frailty (electronic Frailty Index ≥0.25) vs. Non-frail status (electronic Frailty Index 0-0.12) was evaluated on Intensive care unit (ICU) length of stay (days) (exp(B) 2.76, 95% CI 1.83-4.17, p=<0.001). Preoperative frailty (eFI ≥0.25) was associated with a 2.76-fold longer ICU stay (95% CI 1.83–4.17, p<0.001) and 1.87-fold longer hospital stay (p<0.001) after isolated CABG compared to non-frailty.

synapsesocial.com/papers/6ae13d23043bfbd6353328bf https://doi.org/10.34250/jkccn.2026.19.3.97

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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

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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