Frailty phenotypes and their association with health consequences: a comparison of different measures

OBJECTIVES: The frailty index is widely used in clinical and community settings to assess health status. This study aimed to identify the potential phenotypes of frail older adults and examine their relationship with health consequences compared with existing frailty measures. METHODS: The 11-year follow-up data from the Taiwan Longitudinal Study on Aging, covering 5,334 individuals aged ≥ 50 years, were analyzed using random-effects panel logit models. We identified three frailty phenotypes: energy-based frailty (EBF), sarcopenia-based frailty (SBF), and hybrid-based frailty (HBF). Existing frailty measures such as the Study of Osteoporotic Fractures (SOF), Fatigue, Resistance, Ambulation, Illness, and Loss of weight (FRAIL), and Fried scales were applied. We examined their correlation with health outcomes, such as falls and fractures, depression, comorbidities, hospitalization, emergency department visits, and mortality, adjusting for individual-level characteristics. RESULTS: Individuals with only EBF were found to be at a lower risk of falls and fractures than their counterparts with only SBF (adjusted odds ratio AOR = 0.13, 95% confidence interval CI = 0.03-0.46). Depression was less likely in the SBF group than in the EBF group (AOR = 0.02, 95% CI = 0.01-0.05). Hybrid-based frail older adults were more likely to be hospitalized (AOR = 1.84, 95% CI = 1.08-3.14) and have emergency department visits (AOR = 2.03, 95% CI = 1.15-3.58). Frailty assessed using existing measures was associated with adverse health outcomes. CONCLUSION: The proposed frailty phenotype classification differs from the existing frailty measures in its ability to distinguish the corresponding phenotypes underlying various health consequences. Governments may develop strategies based on frailty phenotypes to mitigate adverse health consequences.