Frailty assessment and management using the frailty index: A narrative review

Objective: To provide a comprehensive overview of frailty assessment instruments and evaluate their clinical applicability and prognostic value across healthcare settings.Methods: A structured literature search was conducted in PubMed/MEDLINE, Scopus, and Web of Science for studies published between January 2000 and January 2025.Keywords included "frailty," "frailty index," "frailty phenotype," "Clinical Frailty Scale," "electronic frailty index," and related terms.Peer-reviewed studies evaluating frailty measurement tools and their associations with clinical outcomes in adult populations were included.Titles and abstracts were screened for relevance, followed by full-text review.Due to heterogeneity in study designs and outcome measures, findings were synthesized narratively.Results: Frailty is operationalized using multiple conceptual models, primarily the phenotype-based approach and the cumulative deficit model.Additional instruments, including clinical bedside scales and claims-or electronic health recordbased indices, have been developed to enhance feasibility and scalability.Across diverse populations and clinical settings, frailty consistently predicts adverse outcomes, including mortality, hospitalization, postoperative complications, prolonged length of stay, and healthcare expenditures.However, substantial heterogeneity exists in definitions, thresholds, and implementation strategies, limiting direct comparability across studies.No single instrument demonstrates universal superiority across all contexts.Conclusion: Frailty assessment is a robust predictor of adverse clinical outcomes and represents an important tool for risk stratification.Nevertheless, variability in measurement approaches underscores the need for methodological standardization and prospective validation.Future research should determine whether frailty-guided interventions can translate prognostic identification into improved patient outcomes.