Predictors of Body Weight Loss and Body Weight Loss Maintenance in Children and Adolescents following Inpatient Multidisciplinary Obesity Treatment.

INTRODUCTION: To improve pediatric obesity treatment, this study aimed to identify predictors of body weight loss (BWL) and its maintenance (BWLM) in children and adolescents. METHODS: Data from 59 hospitalized children and adolescents with obesity (aged 9-17, mean 13.4 ± 1.9 years; mean length of stay: 38 ± 9.1 days) were collected at admission (T1), at discharge (T2), and up to 24 months thereafter (T5). Predictors of BWL (ΔT1-T2) (mean 0.33 ± 0.14 BMI z-score) and BWLM (ΔT2-T5) were categorized into demographic, psychometric, and sociometric data, physical condition, autonomic nervous system functions, and eating behavior. Secondary outcomes included changes in body composition and motor performance. Predictors were analyzed using LASSO [Journal of the Royal Statistical Society. 1996;58(1):267-288] and hierarchical regression. RESULTS: Energy density and food intake consistently predicted BWL and BWLM. Body dissatisfaction (p = 0.016), better anger management (less anger-related emotion regulation in the Stress and Stress Coping Questionnaire) (p = 0.031), smell identification skills, higher initial motor performance and strength, and lower initial endurance predicted BWL. A positive attitude toward healthy eating (p < 0.001), its improvement over time (p = 0.027), lower parasympathetic withdrawal - indicated by a smaller relative change in Root Mean Square of Successive Differences (RMSSDs) from baseline to stress (%RMSSD change, p = 0.022) - and high salt sensitivity (p < 0.001) significantly predicted BWLM. CONCLUSION: This study provides initial indications that energy intake, in interaction with psychological and physiological factors, may be relevant to understanding BWL and BWLM in pediatric obesity, warranting further investigation.