Assessing change in body composition in children with Duchenne muscular dystrophy: anthropometry and bioelectrical impedance analysis versus dual-energy X-ray absorptiometry.

BACKGROUND & AIMS: To compare the ability of bioelectrical impedance analysis (BIA) and skinfold thickness (ST) measurements to estimate changes in body composition in Duchenne muscular dystrophy (DMD).
METHODS: A secondary analysis was performed on 26 ambulatory DMD boys aged 3-11 y selected for a randomised trial of glutamine supplementation. We assessed fat free mass (FFM) and percentage fat mass (%FM) by BIA (monofrequency (50kHz) unit), ST measurements and a criterion method, dual-energy X-ray absorptiometry (DXA), and repeated these measures 5 mo later at 3 outpatient clinical investigation centers in France.
RESULTS: When compared with DXA reference method, ST overestimated change in FFM (P<0.01), whereas BIA estimates did not differ from DXA. Concordance plots revealed that when compared with DXA, ST overestimated the increase in FFM (mean: 0.6 kg; 95% CI: 0.17 to 0.99) which led to an underestimation in %FM change (mean: -1.4%; 95% CI: -2.6 to -0.2), whereas BIA estimated change in FFM (mean: -0.05 kg; 95% CI: -0.39 to 0.29) and %FM (mean: 1.3%; 95% CI: -0.06 to 2.7) more accurately.
CONCLUSIONS: BIA method can be used to follow changes in nutritional status of ambulatory DMD children or to evaluate treatment efficacy.

RCT Entities:   Population Interventions Outcomes