Predictors of Changes in Height, Weight, and Body Mass Index After Initiation of Central Nervous System Stimulants in Children with Attention Deficit Hyperactivity Disorder

Abstract

Objective: To identify predictors of changes in height, weight, and body mass index (BMI) in children with attention deficit hyperactivity disorder (ADHD) starting central nervous system (CNS) stimulants.

Study design: There were 230 medication-naïve children aged 5-12 years with ADHD who participated in a randomized trial evaluating the impact of CNS stimulants on growth over 30 months. This observational analysis focused on the 141 participants using study medication for 65 or more days in the first 6-months after starting medication. Biometric variables, ADHD, and oppositional defiant disorder symptom scores at medication initiation, and medication use over the study were examined as predictors of changes in standardized (z) height, weight, and BMI.

Results: Mean changes in z-BMI, z-weight. and z-height were negative throughout the study. The most consistent predictors of change in z-BMI, z-weight, and z-height were percent days medicated and total medication exposure. Children with lower z-height and z-weight at medication initiation experienced greater z-BMI and z-weight decreases over the first 6 months on medication. Greater appetite suppression during dose optimization predicted greater decreases in z-weight over the entire study and a greater decrease in z-height over the first 6 months on medication. z-weight change correlated with z-height change. Behavioral symptoms did not predict changes in z-BMI, z-weight, or z-height.

Conclusions: How much and how often CNS stimulants are used predicts changes in z-BMI, z-weight, and z-height in children. Even smaller and lighter children may be at risk for decreases in z-weight and z-BMI. Parent ratings of appetite during dose titration may serve as feasible indicators of future weight and height change in children using CNS stimulants.

Trial registration: Clinicialtrials.gov: NCT01109849.

Keywords: ADHD; CNS stimulants; children; growth; weight loss.

Copyright © 2021 Elsevier Inc. All rights reserved.

Figures

Figure 1. Study Flowchart

Note. BMI = body mass index, ADHD = Attention-Deficit/Hyperactivity Disorder, CNS + Central Nervous System, MPH = methylphenidate, kg = kilograms. Reprinted from “A Randomized Controlled Trial of Interventions for Growth Suppression in Children With Attention-Deficit/Hyperactivity Disorder Treated With Central Nervous System Stimulants,” by J.G. Waxmonsky, 2020, Journal of the American Academy of Child & Adolescent Psychiatry, 59, p. 1333. Copyright 2020 by the Elsevier. Reprinted with permission.

Figure 2. Association Between Cumulative MPH Intake in First Six Months and Probability of Qualifying for Weight Recovery Treatment

Note. MPH=methylphenidate. Line is model-estimated probability of entering weight recovery treatment (WRT) (from univariate logistic regression). Grey ribbon indicates 95% confidence interval. Dots are the observed proportion of children (i.e., empirical probability) in each quartile of cumulative dose that met WRT criteria (position along x-axis indicates mean dose within quintile). Data are from children ever taking medication (n = 141).

Figure 3. Association Between Medication History Parameters and Changes in z-BMI, z-Weight, and z-Height Across Follow-Up

Note. BMI = body mass index, MPH = methylphenidate. Shows how the correlations between the medication use and change in body measurements evolve across time. Medication usage is calculated over the same interval as change in body measurements (e.g., leftmost red square in the left panel indicates correlation of change in z-BMI in the first 6 months of medication with the percent days medicated in first 6 months after starting medication). Percent days medicated and cumulative intake exhibit large correlations with changes in z-BMI and z-weight that are present at 6 months and persist through the end of follow-up. In contrast, the correlation of percent days medicated and cumulative intake with changes in z-height remains small at 6 months before growing over the follow up period.

Figure 4. Sensitivity Analysis 1: Excluding Children Above the 85th Percentile in BMI at Study Entry

Note. AUXAL = structural auxologic analysis model, BMI = body mass index, ADHD = Attention-Deficit/Hyperactivity Disorder, ODD = Oppositional Defiant Disorder, MPH = methylphenidate, kg = kilograms. Compares correlations based on all children who took medication (black circles) with correlations based on only those with entry BMI below the 85th percentile (white circles). Pairs of correlations with a box around them differed in statistical significance (i.e., one above and one below a threshold of p < .05). As shown, excluding those with entry BMI above the 85th percentile generally had little impact on the magnitude or statistical significance of observed correlations.