[Associations between phase angle measured by bioelectrical impedance and physical frailty, sarcopenia and...

To evaluate the association between phase angle (PA), measured by electrical bioimpedance, and age, comorbidity, physical frailty, and sarcopenia in individuals over 50years old attending a falls clinic.

Data were collected on demographics (age, sex), anthropometric measurements (body mass index [BMI]), comorbidity (CIRS-G score), physical frailty (SHARE-FI score), probable sarcopenia (by handgrip strength and 5 sit-to-stand test [5-STS]), and bioimpedance parameters (PA and sarcopenia as per Sergi's equation). Bivariate correlations and multiple linear regression models were applied to determine association.

The study included 107 patients (61 women) from the Falls and Syncope Unit, Mercer's Institute for Successful Ageing, St James' Hospital, Dublin; with a mean age of 69.8 years, PA of 4.7°, and BMI of 26.4kg/m². PA demonstrated an inverse correlation with SHARE-FI (ρ: -0.23, P=.019), which remained significant after adjusting for age. PA was also inversely correlated with CIRS-G (ρ: -0.40, P<.001); in regression analysis, this association was independent of age (P<.001) and SHARE-FI (P=.539). PA was inversely associated with bioimpedance-confirmed sarcopenia (P=.002) and probable sarcopenia by handgrip strength (ρ: 0.25, P=.009) and 5-STS (ρ: -0.32, P=.001). Among patients with confirmed or probable sarcopenia (n=49), PA was inversely related to CIRS-G (P=.011), independent of age (P=.003) and SHARE-FI (P=.959).

PA decreases with age and is significantly influenced by comorbidities, but not by physical frailty. This relationship persists in patients with confirmed or probable sarcopenia, suggesting that PA could be a valuable marker for assessing the burden of comorbidities in these patients.