Defining and identifying predictors of rapid response to pediatric obesity treatment.

Early weight loss (rapid response [RR]) is associated with better outcomes in adults. Less is known about RR in children enrolled in weight-loss treatment. The aim of the current study was to establish an RR weight-loss threshold following 4 weeks of pediatric obesity treatment and identify characteristics associated with achieving RR. One hundred thirty-seven children aged 8 to 12 with overweight/obesity and parents participated in 6 months of family-based or parent-based treatment. Receiver operating characteristic curves evaluated how weight loss at week 4 related to decreases of 5% at posttreatment and 10% at 6- and 18-month follow-ups of standardized body mass index (BMIz), percentage distance of a child's BMI from the median BMI for sex and age, and percentage above the 95th percentile. Weight loss of 2.4% to 3.4% at week 4 predicted 5% change at posttreatment (AUC's = .68-.75; P's ≤ .002) and 10% change at 6-month follow-up (AUC's = .63-.70; P's ≤ .02). No model was significant at 18-month follow-up. Amount of parent weight (lbs) change at week 4 was associated with child achieving RR. Males and Non-Hispanic Whites were more likely to achieve RR. This threshold could be used to mark early significant progress and guide clinical evaluations of treatment response to paediatric obesity treatment.