Bioelectrical impedance analysis (BIA) phase angle in stroke patients: A systematic review

Phase angle (PhA), a raw variable of bioelectrical impedance analysis (BIA), is an index of muscle structure and quality and might have a potential role in the evaluation of nutritional status. The aim of this systematic review was to evaluate in stroke patients: baseline PhA and its changes during hospital stay; the association of PhA with clinical features of patients, comorbidities, nutritional status or sarcopenia, and clinical outcomes.

Systematic research on electronic databases (PubMed, Scopus, and Web of Science) up to June 14th, 2024 was performed according to PRISMA checklist. Using PECOS strategy, "P" (patients) = stroke patients, "E" (exposure) = lowest PhA values, "C" (comparison) = versus greatest PhA values, "O" (outcome) = nutritional and clinical outcomes, and "S" (study design) = all study types. Methodological quality was assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies (NIH).

Eighteen papers met the inclusion criteria, with a low risk of bias. In stroke patients, evidence suggests that PhA was associated with malnutrition, sarcopenia and sarcopenic obesity, as well as with physical function. In addition, patients with low PhA had a longer hospital stay, higher inflammatory status and higher incidence of urinary tract infections and hospital-acquired pneumonia.

Selected papers, although not conclusive, show that in acute and subacute stroke patients PhA was inversely associated with malnutrition and poor physical function. PhA could be a marker of health status and disease progression. PhA may be useful in a more comprehensive evaluation of nutritional status to be used for diagnosis and implementing therapy.