Components of the Frailty Phenotype in Relation to the Frailty Index : Results From the Toulouse Frailty Platform

Objectives: The frailty phenotype proposed by Fried and colleagues is a widely used frailty screening instrument, consisting of 5 components: weight loss, exhaustion, low grip strength, slow gait speed, and low physical activity. Although equally considered in the computation of the frailty phenotype score, each of the components may present a specific and different weight in clinical practice. The objective of this study was to estimate the weight of each frailty phenotype component in terms of age-related deficit accumulation, defined according to the frailty index (FI) proposed by Rockwood and colleagues. Design: Cross-sectional study. Participants: Data were used from 484 frail older adults admitted to a geriatric day hospital unit of the Toulouse University Hospital. Measurements: The outcome measure was a 35-item FI based on data routinely collected as part of a clinical assessment. Descriptive statistics and linear regression analyses were used to determine which components of the frailty phenotype were most strongly associated with the FI. Results: The mean age of the participants was 83.2 (SD 6.0). All components of the frailty phenotype were significantly associated with the FI, but the magnitude of the associations varied. Linear regression analyses, adjusted for age, sex, and educational level showed that slow gait speed was the most informative component (B = 0.129, P <.001) and weight loss was the least informative component (B = 0.027, P =037). The combination of slow gait speed and low physical activity was the most strongly associated with the FI (B = 0.144, P <.001). Conclusion: Of the 5 components of the phenotype, slow gait speed seems to be the key indicator of frailty.