A New Operational Definition of Frailty: The Frailty Trait Scale

Abstract

ObjectivesTo provide a new instrument to diagnose frailty, the Frailty Trait Scale (FTS), that allows a more precise assessment and monitoring of individuals. DesignProspective population-based cohort study. SettingThe Toledo Study for Healthy Aging, Spain. ParticipantsA total of 1972 men and women aged 65 years or older. MeasurementsWe identified 7 frailty dimensions (energy balance–nutrition, physical activity, nervous system, vascular system, strength, endurance, and gait speed) represented by 12 items. Each item was pondered based on the quintiles of its distribution in the study population. Validity was evaluated by testing its association with factors related to frailty and its predictive value for adverse events. This predictive capacity was further compared with the capacity of 2 well-established frailty models (the frailty phenotype and the Frailty Index). ResultsFTS score was associated with several comorbidities and biomarkers classically associated with frailty. The FTS was associated with the incidence of hospitalization and mortality (hazard ratio associated with a score in the highest quartile [versus the first quartile] = 2.3, 95% confidence interval [CI] 1.6–3.4, and 2.5, 95% CI 1.8–3.6, respectively). Compared with Fried et al's definition, the FTS showed a better predictor for hospitalization in persons younger than 80 (area under the curve [AUC] = 0.65 vs 0.62, P = .01), and for mortality in the oldest group (AUC = 0.77 vs 0.72, P = .02). FTS showed similar predictive value to the Frailty Index. ConclusionFTS associates with many of the factors linked to frailty and has a similar predictive capacity to that provided by the classical instruments. Its characteristics offer some advantages over them, with potential utility in research and clinical practice.