Body composition during outpatient treatment of severe acute malnutrition: Results from a randomised trial testing different doses of ready-to-use therapeutic foods

Background & aims: Treatment of children with uncomplicated severe acute malnutrition (SAM) is based on ready-to-use therapeutic foods (RUTF) prescribed based on body weight and administered at home. Treatment performance is typically monitored through weight gain. We previously reported that a reduced dose of RUTF resulted in weight gain velocity similar to standard dose. Here we investigate the change in body composition of children treated for SAM and compare it to community controls, and describe the effect of a reduced RUTF dose on body composition at recovery.

Methods: Body composition was measured via bio-electrical impedance analysis at admission and recovery among a sub-group of children with SAM participating in a clinical trial and receiving a reduced or a standard dose of RUTF. Non-malnourished children were measured to represent community controls. Linear mixed regression models were fitted.

Results: We obtained body composition data from 452 children at admission, 259 at recovery and 97 community controls. During SAM treatment the average weight increased by 1.20 kg of which 0.55 kg (45%) was fat-free mass (FFM) and 0.67 kg (55%) was fat mass (FM). At recovery, children treated for SAM had 1.27 kg lower weight, 0.38 kg lower FFM, and 0.90 kg lower FM compared to community controls. However, their fat-free mass index (FFMI) was not different from community controls (Δ0.2 kg/m²; 95% CI -0.1, 0.4). No differences were observed in FFM, FM or fat mass index (FMI) between the study arms at recovery. However, FFMI was 0.35 kg/m² higher at recovery with the reduced compared to standard dose (p = 0.007) due to slightly lower height (Δ0.22 cm; p = 0.25) and higher FFM (Δ0.11 kg; p = 0.078) in the reduced dose group.

Conclusions: Almost half of the weight gain during SAM treatment was FFM. Compared to community controls, children recovered from SAM had a lower FM while their height-adjusted FFM was similar. There was no evidence of a differential effect of a reduced RUTF dose on the tissue accretion of treated children when compared to standard treatment.