Integrating frailty and acute illness severity scoring for risk stratification in acute geriatric care: Review and practical guide

Table 2 Key primary studies evaluating the dual-axis assessment and prognostic integration of baseline frailty and acute illness severity scores

Ref.	Study design (n)	Scoring systems	Key findings
Emergency department
Chung et al[82], 2025	Retrospective multi-center (n = 932)	CFS and (NEWS2, qSOFA, REMS)	Combined assessment significantly improved AUROC for predicting hospital admission, ICU admission, and in-hospital mortality (mortality AUROCs 0.77-0.82) compared to isolated scores
Wretborn et al[83], 2024	Prospective multi-center (n = 1832)	CFS and (NEWS, TEWS, RETTS)	Combined assessment significantly improved the AUROC for short-term mortality prognostication (0.53 to 0.82) compared to isolated early warning and triage tools (e.g., NEWS)
Engvig et al[87], 2022	Prospective single-center (n = 195)	CFS and NEWS2	Combined assessment revealed a significant interaction effect (P = 0.003), demonstrating that the prognostic impact of frailty is greater at higher levels of acute illness severity compared to isolated scores
Biuzzi et al[88], 2026	Retrospective single-center (n = 70)	CFS and NEWS2	Combined assessment successfully identified highly frail patients at risk for in-hospital cardiac arrest who presented with deceptively low acute physiological scores
Intensive care unit
Le Maguet et al[2], 2014	Prospective multi-center (n = 196)	FP and SAPS II, CFS and SOFA	Multivariate analysis demonstrated that FP and SAPS II independently predict short-term mortality, while CFS and SOFA concurrently predict long-term mortality
Bagshaw et al[91], 2014	Prospective multi-center (n = 421)	CFS and (SOFA, APACHE II)	Multivariable analysis confirmed that frailty is independently associated with higher in-hospital and long-term mortality after adjusting for SOFA and APACHE II scores. Highlighted mortality increased in a dose-dependent manner with each incremental increase in the frailty score
Guidet et al[92], 2020	Prospective multinational (n = 3920)	CFS and SOFA	Both scores act as powerful, independent predictors of short-term mortality, reinforcing the necessity of dual-axis risk stratification
Haas et al[93], 2021	Prospective multinational (n = 532; sepsis subset of VIP2)	CFS and SOFA	Within the septic sub-cohort, SOFA and CFS scores act as robust, independent predictors of long-term mortality
Bruno et al[94], 2023	IPD meta-analysis (n = 23989)	CFS and SOFA	In geriatric cohort (≥ 65 years), frailty remains a robust, independent predictor of ICU mortality alongside the SOFA score. Highlighted a “frailty continuum” where risk increases progressively across CFS categories
Zeng et al[95], 2015	Prospective single-center (n = 155)	FI and (APACHE II, APACHE IV)	FI captures essential premorbid functional data, increasing the AUROC for mortality from 0.86 to 0.92 (APACHE II) and 0.88 to 0.93 (APACHE IV)
Szűcs et al[84], 2025	Prospective single-center (n = 212)	CFS and (APACHE II, SAPS II)	Integrating the CFS significantly increased the AUROC for mortality from 0.72 to 0.80 (APACHE II) and from 0.79 to 0.84 (SAPS II)
Suh et al[96], 2025	Retrospective multi-center (n = 8220)	CFS and APACHE III-J	Both tools remained strong independent predictors of mortality and prolonged hospitalization in critically ill nonagenarians
Langlais et al[97], 2018	Prospective single-center (n = 189)	CFS and SOFA	Integration of CFS and SOFA yielded a non-significant AUROC improvement for mortality (0.63 to 0.66, P = 0.082)

APACHE: Acute Physiology and Chronic Health Evaluation; AUROC: Area under the receiver operating characteristic curve; CFS: Clinical Frailty Scale; ED: Emergency department; FI: Frailty Index; FP: Frailty phenotype; ICU: Intensive care unit; IPD: Individual patient data; NEWS: National Early Warning Score; NEWS2: National Early Warning Score 2; qSOFA: Quick Sequential Organ Failure Assessment; REMS: Rapid Emergency Medicine Score; RETTS: Rapid emergency triage and treatment system; SAPS II: Simplified Acute Physiology Score II; SOFA: Sequential Organ Failure Assessment; TEWS: Triage Early Warning Score.