RATIONALE: Treating obesity in children and adolescents is complex, given the dynamic nature of growth and development during this life stage. The role of pharmacological treatments in the management of pediatric obesity remains uncertain, particularly with respect to outcomes beyond weight reduction, including quality of life and long-term adverse events.
OBJECTIVES: To assess the benefits and harms of pharmacological interventions for the treatment of obesity in children and adolescents.
SEARCH METHODS: We searched CENTRAL, MEDLINE, the World Health Organization (WHO) International Clinical Trials Registry Platform, and ClinicalTrials.gov on 3 July 2023 without language restrictions. In June 2025, we checked the status of ongoing studies and updated results accordingly.
ELIGIBILITY CRITERIA: We included randomized controlled trials (RCTs) evaluating pharmacological interventions in children (0 to 9 years) and adolescents (10 to 19 years) with essential obesity. Eligible studies administered any medication, at any dose, as monotherapy or in combination, for at least three months and reported outcomes after a minimum follow-up of six months.
OUTCOMES: Critical outcomes were change in body mass index (BMI), change in weight, any adverse events, discontinuation due to adverse events, and incidence or severity of obesity-related outcomes. Important outcomes were health-related quality of life, mental and physical well-being, and obesity-related disability.
RISK OF BIAS: We used the RoB 2 tool to assess bias in the included RCTs.
SYNTHESIS METHODS: We calculated mean differences (MDs) and standardized mean differences (SMDs) for continuous outcomes and risk ratios (RRs) for dichotomous outcomes, with their corresponding 95% confidence intervals (CIs). We used GRADE to assess the certainty of evidence for critical outcomes and quality of life.
INCLUDED STUDIES: We included 37 RCTs with a total of 4218 participants. Two were cross-over trials; 35 were parallel-group trials. We identified seven ongoing studies and six studies as awaiting classification. Of the included studies, 25 involved adolescents only. Eleven studies planned to include both children and adolescents, but only eight actually did. One study intended to include children but did not specify participants' age at inclusion. Trials randomized participants to pharmacological interventions or control alongside common baseline treatments (e.g. behavioral or lifestyle approaches, diet, and physical activity). Of the 37 included studies, 31 used placebo and six used no intervention (baseline treatment alone) as the comparator. The studies were conducted across 17 high-income, six middle-income, and three low-income countries. Length of follow-up ranged from six to 31 months, with a median of 11 months.
SYNTHESIS OF RESULTS: Pharmacological interventions versus placebo Compared to placebo, pharmacological interventions (glucagon-like peptide-1 [GLP-1] receptor agonists, metformin, orlistat, sibutramine, topiramate, phentermine plus topiramate) may reduce BMI (change from baseline) by 1.80 kg/m(95% CI -2.36 to -1.24; I= 87%; 25 studies, 3091 participants; low-certainty evidence) and weight (change from baseline) by 5.47 kg (95% CI -7.45 to -3.50; I= 89%; 20 studies, 2380 participants; low-certainty evidence). Adverse events were frequent. Pharmacological interventions (GLP-1 agonists, sibutramine, phentermine, topiramate) likely make little to no difference in the risk of any adverse events compared to placebo (RR 1.03, 95% CI 1.00 to 1.07; I= 0%; 8 studies, 1877 participants; moderate-certainty evidence). Pharmacological interventions (GLP-1 agonists, metformin, orlistat, sibutramine, phentermine, topiramate) may make little to no difference in the risk of discontinuation due to adverse events, although the risk was slightly higher with the medications (RR 1.50, 95% CI 0.82 to 2.75; I= 17%; 13 studies, 2213 participants; low-certainty evidence). One study (46 participants), comparing sibutramine to placebo, found that there may be little to no difference in the incidence of obesity-related outcomes for adolescents with comorbidities (assessed as changes in glycemia, blood pressure, total cholesterol, and triglycerides). We were unable to pool other data on incidence or severity of obesity-related outcomes. Compared to placebo, pharmacological interventions (GLP-1 agonists, phentermine plus topiramate) likely result in little to no difference in quality of life, assessed with the Impact of Weight on Quality of Life-Kids (IWQOL) questionnaire (MD 1.02, 95% CI -1.94 to 3.98; I= 48%; 4 studies, 741 participants; moderate-certainty evidence). Pharmacological interventions versus no intervention Compared to no intervention, metformin may reduce BMI (change from baseline) by 1.51 kg/m(95% CI -2.29 to -0.73; I= 0%; 3 studies, 151 participants) and weight (change from baseline) by 3.20 kg (95% CI -6.12 to -0.28; 1 study, 42 participants), but the evidence for both outcomes is very uncertain. Compared to no intervention, pharmacological interventions (metformin and orlistat) may increase the risk of discontinuations due to adverse events, but the evidence is very uncertain (RR 13.70, 95% CI 0.83 to 225.43; 2 studies, 84 participants). None of the studies comparing pharmacological interventions to no intervention reported data on adverse events, obesity-related outcomes, and quality of life that could be pooled in meta-analysis. Only eight of the 37 included studies enrolled children, and data were seldom disaggregated by age, limiting the ability to draw conclusions about benefits or harms in children. 2 2 2 2 2 2 2 2
AUTHORS' CONCLUSIONS: This review includes clinical trials assessing the benefits and harms of pharmacological treatments - including GLP-1 agonists, metformin, orlistat, phentermine, sibutramine, and topiramate - for weight management in adolescents with obesity. Evidence suggests that pharmacological treatments may result in small reductions in BMI and weight, which could be clinically important, although effects vary by medication. Evidence on desirable and undesirable effects in children is scant. Uncertainties remain about the optimal duration of treatment, consequences of treatment discontinuation, and long-term benefits and harms, particularly considering the physiology of children and impact on growth. Studies with longer follow-up are needed to evaluate outcomes beyond BMI and weight change, including the potential effects of treatment discontinuation.
FUNDING: The Department of Nutrition and Food Safety at the WHO commissioned and provided financial support for this work. WHO acknowledges financial support from the Norwegian Agency for Development Cooperation (NORAD), the Swedish International Development Cooperation Agency (SIDA), the Government of the Grand Duchy of Luxembourg, the Government of Germany (BMG), and the Government of Greece to the WHO Department of Nutrition and Food Safety.
REGISTRATION: Our protocol is registered in PROSPERO: www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023433123.
