Bioelectrical impedance parameters and nutritional status of pediatric patients with hematological malignancies: a cross-sectional study.

BACKGROUND: treatment of pediatric patients with hematologic malignancies (HM) affects their nutritional status and body composition. Bioelectrical impedance analysis (BIA) parameters [resistance (R), reactance (Xc), phase angle (PhA)] are non-invasive tools for assessing these changes. The objective was to compare standardized BIA parameters [R/height (h), Xc/h] and PhA of pediatric patients with HM against a healthy reference population. METHODS: pediatric patients with HM (active treatment), anthropometric parameters [height, weight, mid-upper arm circumference (MUAC), waist circumference (WC), triceps skinfold thickness (TSF), handgrip strength (HGS)] and BIA parameters were measured before chemotherapy. Data were compared with an ethnically matched healthy reference population using t-tests and multivariate analysis of covariance (MANCOVA) with WC. RESULTS: twenty-seven children (99 months) participated. Compared to the reference population, patients showed higher R/ht (+47.8 ohms/m, p = 0.020), lower Xc/ht (-26.2 ohms/m, p < 0.001), and PhA (-2.79°, p < 0.001). HGS was lower (-2.36 kg, p = 0.002), while WC (+9.38 cm, p < 0.001), TSF (+1.60 mm, p = 0.041), and arm fat area (+2.98 cm², p < 0.001) were higher. After adjusting for WC, the differences persisted (Pillai trace = 0.773, p < 0.001). PhA remained lower in patients (adjusted difference -2.78°, p < 0.001) and was independent of WC (p = 0.969). CONCLUSIONS: patients showed impaired cellular health (low PhA) and muscle function (low HGS) coexisting with increased adiposity (WC, TSF). The reduction in PhA was independent of WC, reinforcing its role as a specific marker of cellular deterioration. Direct BIA parameters, particularly PhA, offer a valuable non-invasive tool for the early identification of nutritional risk.