Body cell mass estimation by whole body potassium counter and its association with protein energy wasting in Indian children with chronic kidney disease.

Abstract

Background: Body cell mass (BCM) is an ideal indicator of nutritional status that is independent of hydration, when measured by the reference tool whole body potassium counter (WBPC). The WBPC calculates total body potassium (TBK) through naturally occurring intracellular potassium isotope (K₄₀) to derive BCM. This study aimed to standardise the WBPC measurement of BCM in children, assess BCM in children with CKD stages 2-5D, and explore its association with nutritional status of protein energy wasting (PEW).

Methods: The WBPC was standardised using differing body size phantoms and Monte Carlo simulations. TBK (kg), BCM (kg) and BCM indexed to height (BCMI) were measured at baseline and twice every 3-6 months in children with CKD 2-5D and compared with healthy controls. PEW was diagnosed using specific criteria.

Results: The accuracy and variance of BCM measurement was 97.45% and 1.8%, respectively. Among 74 children studied, mean BCMI (Kg/m) in 74 with CKD 2-5, 38 on dialysis and 50 healthy controls were 4.6 ± 1.2, 4.1 ± 1.0, and 5.1 ± 1.0, respectively. The BCMI was significantly lower in those with CKD 2-5 and dialysis compared to controls [p = 0.011, p < 0.001, respectively]. However, there was no significant difference in BCMI between those with and without PEW in the cohort. The BCMI correlated with body mass index (BMI) in both the groups [CKD 2-5: r = 0.58, p < 0.001; Dialysis: r = 0.51, p = 0.001].

Conclusion: Standardized measures of BCM by WBPC showed that it was lower in children with CKD 2-5D compared to controls, independent of PEW status. BMI may potentially serve as a surrogate measure of BCMI in this population.