---
title: "FI-Lab: Automated laboratory-based frailty index for acute care and its prognostic performance"
id: "plos-medicine-3-evaluation-of-the-fi-lab-a-laboratory-based-automated-frailty-index-for-acute"
canonical_url: "https://medichelpline.com/clinical-feed/plos-medicine-3-evaluation-of-the-fi-lab-a-laboratory-based-automated-frailty-index-for-acute"
content_type: "clinical_feed_article"
specialty: "General"
source_name: "PLOS Medicine"
source_url: "https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004"
published_at: "2026-09-01T14:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# FI-Lab: Automated laboratory-based frailty index for acute care and its prognostic performance
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/plos-medicine-3-evaluation-of-the-fi-lab-a-laboratory-based-automated-frailty-index-for-acute
- **Specialty:** [General](https://medichelpline.com/clinical-feed/general.md)
- **Primary Source:** PLOS Medicine
- **Source URL:** [Original Journal Publication](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004)
- **Published At:** 2026-09-01T14:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- The study evaluated an automated, laboratory-based frailty index (**FI-Lab**) as a scalable measure of patient vulnerability across adult ages in acute and community settings. - Retrospective multicohort analysis used three large datasets: MIMIC-IV-ED (Boston ED; 227,736 visits, 113,032 patients; 2011–2019), King’s College Hospital ED (KCH; 152,305 visits, 96,843 patients; 2017–2020), and UK Biobank (community cohort; 492,703 participants; 2006–2010). - The primary outcome was **1-year all-cause mortality**; secondary outcomes included hospital admission and readmission; performance was compared with chronological age and the National Early Warning Score 2 (**NEWS2**). - FI-Lab configurations were varied by test selection strategy, number of laboratory tests, and minimum test thresholds; sensitivity analyses examined age, sex, ethnicity, and model types. - A configuration using 25 commonly ordered laboratory tests (minimum 15 required) produced hazard ratios for 1-year mortality approaching those of chronological age and exceeding NEWS2; combined-model hazard ratios per SD increase were reported for each dataset in the source. - Discrimination of FI-Lab plateaued when using about **20–40 tests**, indicating a core set in that range captures most signal. - The FI-Lab was robust across subject groupings (age, sex, ethnicity, healthcare setting) and offers an automated measure that requires no extra testing or manual data entry. - Limitations: retrospective design; authors note need for prospective evaluation, including trials to assess real-time clinical impact. - Data availability: MIMIC-IV-ED and UK Biobank access pathways noted; KCH data not publicly available. Analysis code for FI-Lab is available on GitHub and Zenodo as reported in the source. - Funding and competing interests were disclosed; recommendations call for further research to determine whether real-time FI-Lab access improves clinical decision-making or patient outcomes.
## Clinical Analysis & Structured Key Points
[ Skip to main content ](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#main-content) Advertisement * [plos.org](https://plos.org/) * [Create account](https://community.plos.org/registration/new) * [Sign in](https://journals.plos.org/user/secure/login?page=%2Fplosmedicine%2Farticle%3Fid%3D10.1371%2Fjournal.pmed.1005004) * * About * Browse * Publish * [](https://journals.plos.org/plosmedicine/ "PLOS Medicine") * Search [advanced search](https://journals.plos.org/plosmedicine/search) * 0 [Save](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#savedHeader) [Total Mendeley and Citeulike bookmarks.](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#savedHeader) * 0 [Citation](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#citedHeader) [Paper's citation count computed by Dimensions.](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#citedHeader) * 13 [View](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#viewedHeader) [PLOS views and downloads.](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#viewedHeader) * 0 [Share](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#discussedHeader) [Sum of Facebook, Twitter, Reddit and Wikipedia activity.](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004#discussedHeader) Open Access Peer-reviewed Research Article # Evaluation of the FI-Lab, a laboratory-based, automated frailty index for acute care: A multicohort study * Hugh Logan Ellis, Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Software, Validation, Visualization, Writing – original draft, Writing – review & editing Affiliations Department of Biostatistics and Health Informatics, King’s College London, London, United Kingdom, Division of Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada, King’s College Hospital, London, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0002-6428-0158 ](https://orcid.org/0000-0002-6428-0158 "ORCID Registry") ⨯ * Peter Hanlon, Roles Data curation, Formal analysis, Investigation, Methodology, Software, Validation, Writing – original draft, Writing – review & editing Affiliation School of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0002-5828-3934 ](https://orcid.org/0000-0002-5828-3934 "ORCID Registry") ⨯ * Liam Dunnell, Roles Writing – original draft, Writing – review & editing Affiliation King’s College Hospital, London, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0002-4642-9334 ](https://orcid.org/0000-0002-4642-9334 "ORCID Registry") ⨯ * Martin Whyte, Roles Writing – review & editing Affiliations King’s College Hospital, London, United Kingdom, University of Surrey, Guildford, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0002-2897-2026 ](https://orcid.org/0000-0002-2897-2026 "ORCID Registry") ⨯ * Daniel H. J. Davis, Roles Writing – review & editing Affiliations Institute of Health Informatics, University College London, London, United Kingdom, University College London, London, United Kingdom ⨯ * Josephine Bates, Roles Conceptualization, Writing – review & editing Affiliation King’s College London, London, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0002-9396-1972 ](https://orcid.org/0000-0002-9396-1972 "ORCID Registry") ⨯ * Adeel Jafri, Roles Conceptualization, Writing – review & editing Affiliation St James’s University Hospital, Leeds, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0009-0004-1280-8506 ](https://orcid.org/0009-0004-1280-8506 "ORCID Registry") ⨯ * Diana Shamsutdinova, Roles Data curation, Formal analysis, Validation, Writing – review & editing Affiliation Department of Biostatistics and Health Informatics, King’s College London, London, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0003-2434-3641 ](https://orcid.org/0000-0003-2434-3641 "ORCID Registry") ⨯ * James T. Teo, Roles Supervision, Writing – review & editing Affiliations Department of Biostatistics and Health Informatics, King’s College London, London, United Kingdom, King’s College Hospital, London, United Kingdom, Cleveland Clinic Hospital London, London, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0002-6899-8319 ](https://orcid.org/0000-0002-6899-8319 "ORCID Registry") ⨯ * Zina Ibrahim, Roles Supervision, Writing – review & editing Affiliation Department of Biostatistics and Health Informatics, King’s College London, London, United Kingdom [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0001-6203-2727 ](https://orcid.org/0000-0001-6203-2727 "ORCID Registry") ⨯ * Kenneth Rockwood Roles Funding acquisition, Investigation, Methodology, Project administration, Supervision, Writing – original draft, Writing – review & editing * E-mail: Kenneth.Rockwood@dal.ca Affiliations Division of Geriatric Medicine, Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada, Centre for Health Care of the Elderly, Nova Scotia Health, Halifax, Nova Scotia, Canada [ ![ORCID logo](https://journals.plos.org/resource/img/orcid_16x16.png) https://orcid.org/0000-0002-6674-995X ](https://orcid.org/0000-0002-6674-995X "ORCID Registry") ⨯ # Evaluation of the FI-Lab, a laboratory-based, automated frailty index for acute care: A multicohort study * Hugh Logan Ellis, * Peter Hanlon, * Liam Dunnell, * Martin Whyte, * Daniel H. J. Davis, * Josephine Bates, * Adeel Jafri, * Diana Shamsutdinova, … * James T. Teo, * Zina Ibrahim ![PLOS](https://journals.plos.org/resource/img/logo-plos-full-color.svg) x * Published: September 1, 2026 * * [Article](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004) * [Authors](https://journals.plos.org/plosmedicine/article/authors?id=10.1371/journal.pmed.1005004) * [Metrics](https://journals.plos.org/plosmedicine/article/metrics?id=10.1371/journal.pmed.1005004) * [Comments](https://journals.plos.org/plosmedicine/article/comments?id=10.1371/journal.pmed.1005004) * [Media Coverage](http://plos.altmetric.com/details/doi/10.1371/journal.pmed.1005004) * [Peer Review](https://journals.plos.org/plosmedicine/article/peerReview?id=10.1371/journal.pmed.1005004) * [Abstract](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#abstract0) * [Author summary](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#abstract1) * [Introduction](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#sec007) * [Methods](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#sec008) * [Results](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#sec017) * [Discussion](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#sec023) * [Supporting information](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#sec024) * [Acknowledgments](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#ack) * [References](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004#references) * [Reader Comments](https://journals.plos.org/plosmedicine/article/comments?id=10.1371/journal.pmed.1005004) * [Figures](https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005004) [?](https://journals.plos.org/plosmedicine/s/accepted-manuscripts#loc-early-version) ## This is an uncorrected proof. ## Abstract ### Background Laboratory-based frailty indices (FI-Lab) have shown promise in geriatric medicine research. We aimed, in diverse samples, to determine the optimal construction of an FI-Lab for acute care and evaluate its validity as a measure of latent health status across the adult life span. ### Methods and findings Our retrospective multicohort study used emergency department encounters in Boston, USA (MIMIC-IV-ED; 2011–2019) and London, UK (King’s College Hospital (KCH); 2017–2020); and a community-based cohort in the UK (UK Biobank; 2006–2010). We evaluated FI-Lab configurations by varying test selection strategies, number of tests, and minimum test thresholds. Sensitivity analyses examined performance across age, ethnicities, sexes, and model types to identify potential blind spots. The primary outcome was 1-year all-cause mortality. We analysed 227,736 visits (113,032 patients) from MIMIC-IV-ED; 152,305 visits (96,843 patients) from KCH; and 492,703 UK Biobank. An FI-Lab calculated from 25 commonly ordered tests (minimum 15 required) demonstrated hazard ratios for 1-year mortality approaching those of chronological age and exceeding the National Early Warning Score 2 (NEWS2). In combined models, hazard ratios for FI-Lab per standard deviation increase were 2.00 (95 %CI [1.99, 2.09]; _p_ ). MIMIC-IV-ED data are freely available upon request to the Massachusetts Institute of Technology ( ). King’s College Hospital data are not publicly available; access is typically limited to approved researchers who meet the relevant data access and ethics requirements. Interested users can contact the King’s Electronic Records Research Interface (KERRI) at kch-tr.cogstackrequests@nhs.net. All analysis code for FI-Lab is available at GitHub ( ) or . **Funding:** This work was supported by the DRIVE-Health, King’s College London funded Centre for Doctoral Training (CDT) in Data-Driven Health ( ), and a Dalhousie University Internal Medicine Research Foundation Research Fellowship (UIMRF; ), both awarded to H.L.E. Z.I. is supported by the NIHR Biomedical Research Centres at South London and Maudsley NHS Foundation Trust and University College London Hospitals, King’s College London ( ), and Innovate UK (grant 10104845; ). UK Biobank was established by the Wellcome Trust, Medical Research Council, Department of Health, Scottish Government, and the Northwest Regional Development Agency, with additional funding from the Welsh Assembly Government, British Heart Foundation, Cancer Research UK, Diabetes UK, and National Institute for Health and Care Research (NIHR) ( ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. **Competing interests:** I have read the journal’s policy and the authors of this manuscript have the following competing interests: KR has asserted copyright over the Clinical Frailty Scale and (with Olga Theou) the Pictorial Fit-Frail Scale, which are made freely available for not-for-profit use for education and research, and health care with completion of a permission agreement stipulating users will not change, charge for nor commercialize the scales. For-profit entities (including pharma) pay a licensing fee, 15% of which is retained by the Dalhousie University Office of Commercialization and Innovation Engagement. The remainder of the license fees are donated to the Dalhousie Faculty of Medicine Advancement Fund and the QEII Health Sciences Centre Research Foundation. In the past five years, licenses have been negotiated with AstraZeneca UK Ltd, BioAge Labs Inc, Biotest AG, Cellcolabs AB, Congenica, Cook Research Inc, Faraday Pharmaceuticals Inc, Icosavax Inc, KCR S.A., Pfizer Inc, Qu Biologics Inc, Renibus Therapeutics Inc, Synairgen Research Ltd, and W.L. Gore Associates Inc. In the past 5 years KR has received honoraria for invited lectures, rounds and academic symposia on frailty from the Atria Institute of New York, the Australia New Zealand Society of Geriatric Medicine, the British Geriatrics Society, the Canadian Geriatrics Society, the Canadian Translational Geroscience Network, the China & Sichuan Provincial People’s Hospital (virtual), the Chinese Geriatrics Society (virtual), Columbia University, Fraser Health Authority, the International Conference of Geriatric Emergency and Critical Care Medicine, the International Conference on Far-UVC Science and Technology, McMaster University, the Spanish Society of Geriatrics, the University of British Columbia, the University of Connecticut at Hartford, the University of Nebraska-Omaha, and the Wake Forest Baptist Health Center for Health Care Innovation. KR recently chaired a data safety monitoring board for EIP Pharma Inc., on a study funded jointly by with the National Institute on Aging. In the past 5 years, he has served as a member of the NIA-funded ADMET-2 advisory board (Johns Hopkins) and the Wake Forest University Medical School Center advisory board. KR is co-founder of Ardea Outcomes (DGI Clinical until 2021), which in the past 5 years has had contracts with pharma and device manufacturers (Danone, Hollister, INmune, Novartis, Takeda) as well as the LuMind IDSC Down Syndrome Foundation. KR is named on a US patent application submitted by Ardea Outcomes Inc for “Electronic Goal Attainment Scaling” (patent number US20230402138A1). J.T.T. has received research grant funding from National Institutes for Health Research (NIHR), Health Data Research UK (HDR), Innovate UK, Office of Life Sciences, Epilepsy Research Institute, British Heart Foundation, Responsible AI Adoption Unit, OneLondon Secure Data Environment, Kings Health Partners, and Engineering & Physical Sciences Research Council (ESPRC). J.T.T. has also received research equipment support from Nvidia, Elastic and Scan Computing. J.T.T. is director and shareholder of CogStack Ltd. None of the funders had any say on the content of this work. **Abbreviations:** APACHE, Acute Physiology and Chronic Health Evaluation; CI, confidence intervals; COV, coefficient of variation; ED, emergency department; EHRs, Electronic health records; FI-Lab, laboratory-based frailty index; KCH, King’s College Hospital; ML, machi
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