Association between hospital frailty risk score and length of hospital stay, hospital mortality, and hospital costs for all adults in England: a nationally representative, retrospective, observational cohort study

Street, Andrew ORCID: 0000-0002-2540-0364, Maynou, Laia ORCID: 0000-0002-0447-2959, Blodgett, Joanna M. and Conroy, Simon (2025) Association between hospital frailty risk score and length of hospital stay, hospital mortality, and hospital costs for all adults in England: a nationally representative, retrospective, observational cohort study. The Lancet Healthy Longevity. ISSN 2666-7568

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Abstract

Background: Studies have shown that the Hospital Frailty Risk Score (HFRS) is significantly associated with length of stay, in-hospital mortality, and costs in people aged 75 years and older. However, its applicability to hospitalised adults of all ages is unclear. We aimed to examine the association between the HFRS and these three outcomes in a nationally representative sample of adults aged 18 years and older, admitted for emergency hospital care. Methods: The analytical sample comprised 1 478 554 emergency hospital admissions for 653 294 patients—a 5% random sample of all emergency admissions for those aged 18 years and older to any English National Health Service acute hospital between April 1, 2011, and March 31, 2019. Admissions were categorised into zero (HFRS=0), low (0< HFRS <5), intermediate (5≤ HFRS ≤15), or high (HFRS >15) frailty risk categories. We analysed the association between these categories and three outcomes: length of stay (Poisson model), in-hospital death (probit model); and hospital costs (generalised linear model). Models controlled for patient characteristics and temporal effects and were run separately across nine age groups (18–24 years, 25–34 years, 35–44 years, 45–54 years, 55–64 years, 65–74 years, 75–84 years, 85–94 years, and ≥95 years). Findings: The prevalence of high frailty risk increased with age, from 210 (0·2%) of 96 296 admissions for those aged 18–24 years to 9414 (42·0%) of 22 431 admissions for those aged 95 years and older. There were significant associations between frailty risk and both length of stay and costs across all age groups; the magnitude of the associations increased with age. For example, for those aged 18–24 years with high frailty risk, length of stay was 4·5 days (95% CI 3·8–5·3) longer and costs were £1217 higher (796–1638) than for someone with a zero frailty risk. For those aged 95 years and older with high frailty risk, length of stay was 15·3 days (13·5–17·1) longer and costs were £2557 higher (2234–2880) than for someone with a zero frailty risk. The association between frailty risk and in-hospital mortality increased up to age 65–74 years—those in this age group with high frailty risk had a probability of dying in hospital that was 2·3% greater (1·99–2·61) than those with zero frailty risk. This association decreased for older age groups. Interpretation: Although designed for people aged 75 years and older, the HFRS was significantly associated with length of stay, in-hospital death, and hospital costs for all adults admitted to hospital, with a greater magnitude of effect with increasing age. Frailty dashboards that use the HFRS for older people could be extended to all people aged 18 years and older, offering the potential for holistic, frailty attuned interventions for younger people, such as earlier life course interventions to delay or prevent frailty and related outcomes. Funding: National Institute for Health and Care Research.

Item Type:	Article
Additional Information:	© 2025 The Author(s)
Divisions:	Health Policy LSE
Subjects:	R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
Date Deposited:	02 Sep 2025 13:30
Last Modified:	02 Sep 2025 13:30
URI:	http://eprints.lse.ac.uk/id/eprint/129360

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