Body composition in patients with short bowel syndrome: an assessment by bioelectric impedance spectroscopy (BIS) and dual-energy absorptiometry (DXA)

OBJECTIVE: To describe body composition in patients with short bowel syndrome (SBS) by using bioelectric impedance spectroscopy (BIS), dual-energy X-ray absorptiometry (DXA) measurements and anthropometrical-derived estimates. SUBJECTS: In all, 19 patients were included, mean age 54 y, range 36-77 (F/M=11/8). Mean BMI was 21.5 kg/m(2). Eight patients were on home parenteral nutrition (HPN). METHODS: Total body water (TBW), intracellular water and extracellular water were assessed by BIS. TBW were derived from DXA. Fat-free mass (FFM) was assessed by BIS and DXA. TBW and FFM were predicted according to an empirical formula. Differences were analysed using the Bland-Altman method. RESULTS: The mean difference between TBW (DXA) and TBW (BIS) was -1.1 l in women and -1.8 l in men. For FFM, the mean difference between FFM (DXA) and FFM (BIS) was -1.7 kg in women and -2.5 kg in men. The mean difference between TBW (DXA) and TBW (BIS) for all patients was -1.2 l and limits of agreement were (-7.80-5.40). Hydration of FFM assessed by BIS gave a mean of 0.75 (0.08). CONCLUSION: The limits of agreement (Bland-Altman) between DXA and BIS were wide, indicating that methods are not interchangeable, which limits its clinical utility. Most of our patients with SBS were maintained in a stable clinical condition within normal limits of body weight and BMI. FFM and TBW did not appear to be altered in ileostomates or those on HPN.