Acceso usuarios
Santiago, Chile
Introduction: Phase angle (PhA) derived from bioelectrical impedance analysis (BIA) is a non-invasive biomarker that reflects cell membrane integrity and nutritional status. Although several cut-off points have been proposed to identify high-risk individuals, the relationship between PhA quartiles and mortality risk has not been systematically explored.
Objective: This study aimed to evaluate the association between quartiles of PhA and all-cause mortality in older adults.
Methods: In this prospective cohort study, PhA was measured at baseline using standardized BIA procedures, and participants were stratified into quartiles (Q1–Q4) according to the distribution of PhA values. Mortality and follow-up time were recorded. Cox proportional hazards models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for each quartile, using Q1 as reference. Model 1 was unadjusted, Model 2 adjusted for age and sex, and Model 3 further adjusted for the Charlson Comorbidity Index.
Results: A total of 398 older adults were analyzed. Participants in higher PhA quartiles had lower comorbidity scores and improved survival. In the fully adjusted model, HRs (95% CI) for Q2, Q3, and Q4 versus Q1 were 0.48 (0.24–0.95), 0.43 (0.20–0.91), and 0.27 (0.11–0.67), respectively (p-trend = 0.002). Each increment in PhA quartile corresponded to a substantial reduction in mortality risk, indicating a robust dose-response relationship independent of age, sex, and multimorbidity.
Conclusions: Quartile-based analysis revealed a graded, inverse relationship between PhA and mortality. Higher PhA values independently predicted greater survival, supporting its use as an accessible biomarker for risk stratification and early intervention in geriatric care.
