Phenotypes of frailty and their mortality and disability implications

Frailty is a geriatric syndrome defined as increased vulnerability to stressors due to dysfunction in multiple physiological systems, measured by different tools.

To assess whether participants characterized as frail by multiple scales simultaneously have differentiated risks.

Prospective population-based cohort study.

Community-dwelling adults from the first wave of The Toledo Study for Healthy Aging (TSHA), including a total of 1.563 participants with a mean age of 74.51 years. Frailty was assessed using three tools: the Frailty Index (FI), the Fried Phenotype, and the Frailty Trait Scale (FTS-5). Eight groups were defined based on the presence or absence of frailty according to these scales. Associations between frailty categories and outcomes were evaluated using multivariate Cox proportional hazards models for mortality and logistic regression models for incident and worsening disability.

The FTS-5 scale identified the highest number of frail participants, suggesting it may be the most sensitive tool for detecting early physiological changes related to aging. Risk of adverse events varied depending on the specific combination of frailty criteria met. Individuals classified as frail by both FTS-5 and FI exhibited the highest mortality risk, exceeding that of participants frail on all three scales. Regarding worsening health or disability, the highest risk was among those frails on all three scales, followed closely by the FTS-5-FI group.

Our findings highlight variability in frailty assessment, showing that different instruments capture complementary aspects of frailty and that their combined use may improve risk stratification.