Comparison of 4 Frailty Measurements in Relation to Ageing, Physical Performance, and All-Cause Mortality

Frailty instruments predict mortality and functional decline, but their performance across sex and age groups has not been compared.

This is a prospective population-based cohort study conducted between October 2014 and September 2016, with mortality follow-up through December 31, 2022.

This study was conducted in Saarland, Germany, and included 2000 community-dwelling adults aged 63 to 89 years with complete data on 4 frailty instruments.

We conducted a population-based cohort study of 2000 participants aged 63 to 89 years. The Clinical Frailty Scale (CFS), Fried Frailty Phenotype (FFP), Frailty Index (FI), and FRAIL Scale (FS) were compared with respect to their cross-sectional associations with poor physical performance (Short Physical Performance Battery score ≤6 points) and longitudinal associations with all-cause mortality in models adjusted for age, sex, education, and smoking status.

The frailty prevalence was similar when assessed with the FFP (18.1%), FI (18.7%), FS (18.5%), and CFS (20.2%), and increased with age except for the FS. Frailty assessed by all instruments was significantly associated with poor physical performance and all-cause mortality. The FFP exhibited the strongest association with poor physical performance [odds ratio (OR), 9.19; 95% CI, 4.87-14.30], whereas the ORs of the other instruments had comparable OR point estimates of about 4. The FI yielded the strongest hazard ratio (HR) with mortality (HR, 3.83; 95% CI, 2.47-5.94), closely followed by the CFS and FS, whereas the FFP had the weakest association (HR, 2.62; 95% CI, 1.76-3.90). The FFP showed the best discrimination for poor physical performance across age and sex subgroups. For mortality, the FI showed the best discrimination overall, except among men, in whom the FS performed best.

This study showed that the performance of frailty instruments varies strongly by outcome of interest, sex, and age. This has implications for the choice of the frailty instrument to use in different clinical and research contexts.