Frailty measurement in research and clinical practice: An updated review

Frailty is a highly prevalent geriatric condition, affecting between 12-24% of older adults globally. It remains a major cause of morbidity and mortality in older adults. Incorporating frailty measurement into clinical decision making can guide optimal patient care. This updated review presents an outline of current frailty definitions and measurement approaches in both research and clinical practice, including: Fried's frailty phenotype; Rockwood and Mitnitski's Frailty Index (FI) of cumulative deficits; Clinical Frailty Scale (CFS); Fatigue, Resistance, Ambulation, Illness and Loss of weight (FRAIL) scale; Edmonton Frail Scale (EFS); electronic Frailty Index (eFI); Hospital Frailty Risk Score (HFRS); Study of Osteoporotic Fractures (SOF) Index; Tilburg Frailty Indicator (TFI); Groningen Frailty Indictor (GFI); Multidimensional Prognostic Index (MPI); the Kihon Checklist (KCL); Geriatric 8 (G8) for oncology; the Essential Frailty Toolset (EFT) for cardiology; plus gait speed and grip strength. The main strengths and limitations of existing frailty measurements are summarised, including how well these measurements operationalise frailty in terms of their accuracy in identifying frailty, their basis on biological causative theory, and their ability to reliably predict patient outcomes and response to potential therapies.