Efficacy and Safety of GLP-1 Receptor Agonists, Dual Agonists, and Retatrutide for Weight Loss in Adults With Overweight or Obesity: A Bayesian NMA.

This Bayesian network meta-analysis (NMA) synthesized evidence from 19 randomized controlled trials (RCTs) enrolling 29,506 adults with overweight or obesity (BMI ≥ 25 kg/m²) to compare the weight-loss efficacy and safety of GLP-1 receptor agonists (liraglutide, semaglutide), dual agonists (tirzepatide, survodutide), and the triple agonist retatrutide against placebo over at least 36 weeks. The study found that retatrutide and dual agonists achieved equivalent mean weight loss (approximately −11.0 kg), both outperforming GLP-1 receptor agonists (approximately −9.0 kg). Retatrutide showed the highest odds of achieving ≥15% weight loss (OR 54.6), followed by dual agonists (OR 16.4) and GLP-1 receptor agonists (OR 9.0). However, retatrutide was also associated with the highest adverse event risk. Meta-regression analyses indicated that type 2 diabetes mellitus attenuated weight loss across all drug classes, while female-dominant and higher-BMI cohorts showed enhanced outcomes. Limitations include indirect comparisons inherent to NMA methodology, heterogeneity across trials in baseline characteristics, and the fact that retatrutide data remain from earlier-phase trials. The authors recommend individualized treatment selection based on patient-specific factors.

Why this grade: The NMA pools 19 RCTs with nearly 30,000 adults, providing high-quality indirect comparative evidence across multiple approved and investigational agents in the relevant human population.