Fat mass index performs best in monitoring management of obesity in prepubertal children

Objective: An early and accurate recognition of success in treating obesity may increase the compliance of obese children and their families to intervention programs. This observational, prospective study aimed to evaluate the ability and the time to detect a significant reduction of adiposity estimated by body mass index (BMI), percentage of fat mass (%FM), and fat mass index (FMI) during weight management in prepubertal obese children. Methods: In a cohort of 60 prepubertal obese children aged 3–9 years included in an outpatient weight management program, BMI, %FM, and FMI were monitored monthly; the last two measurements were assessed using air displacement plethysmography. The outcome measures were the reduction of >5% of each indicator and the time to achieve it. Results: The rate of detection of the outcome was 33.3% (95% CI: 25.9–41.6) using BMI, significantly lower (p