Frailty or sarcopenia: which is a better indicator of mortality risk in older adults?

Background: Despite the different conditions, frailty and sarcopenia overlap regarding their common link: the assessment of walking speed and muscle strength. This study aimed to compare the frailty phenotype to the sarcopenia using different cut-off points for low grip strength to determine which better identifies mortality risk over a 14-year follow-up period.

Methods: 4597 participants in the English Longitudinal Study of Ageing. Frailty was measured using the Fried phenotype. Sarcopenia (European Working Group on Sarcopenia in Older People 2) was defined using different cut-off points for low grip strength (<36, <32, <30, <27 and <26 kg for men and <23, <21, <20 and <16 kg for women), low skeletal muscle mass index (<9.36 kg/m² for men and<6.73 kg/m² for women) and slowness (gait speed: ≤0.8 m/s). Cox models were run and adjusted for sociodemographic, behavioural and clinical factors.

Results: When the coexistence of frailty and sarcopenia is considered, only the cut-off points <36 kg for men and <23 kg for women to define low grip strength identified the risk of mortality among individuals classified as having probable sarcopenia (HR=1.17, 95% CI 1.02 to 1.34), sarcopenia (HR=1.31, 95% CI 1.07 to 1.60) and severe sarcopenia (HR=1.62, 95% CI 1.33 to 1.96). In this situation, frailty identified the mortality risk (HR=1.49, 95% CI 1.22 to 1.81), whereas pre-frailty did not. Sarcopenia using other cut-off points for defining low grip strength did not identify mortality risk.

Conclusion: Sarcopenia using <36 kg for men and <23 kg for women as cut-off points seems to be better than the frailty phenotype for identifying the risk of mortality in older adults.