Background and AimEmerging evidence suggests that weight loss associated with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may be in part attributable to changes in lean mass, which has potential clinical implications. This study evaluates the disproportionate reporting of muscle atrophy in association with GLP-1 RA therapy using real-world global data.. MethodsWe analyzed reports of muscle atrophy submitted to the FDA Adverse Event Reporting System (FAERS) database from October 2003 to March 2024 using the validated pharmacovigilance tool OpenVigil 2.1. Disproportionality was assessed using reporting odds ratios (RORs) with 95 % confidence intervals (CIs), the standard metric for pharmacovigilance signal detection worldwide. To contextualize associations, disproportionality estimates were calculated using niacin, simvastatin, and the complete FAERS database (all other drugs) as comparators. ResultsA total of 142 cases of muscle atrophy were identified with GLP-1 RA therapy, the majority occurring in adults aged 18-64 years (43 % female, 57 % male). Disproportionality analysis showed pharmacovigilance signals for semaglutide (ROR = 2.39, 95 % CI = 1.63-3.52) and tirzepatide (ROR = 1.69, 95 % CI = 1.14-2.50), indicating increased reporting of muscle atrophy relative to all other drugs in FAERS. In contrast, exenatide (ROR = 0.26, 95 % CI = 0.12-0.55) and liraglutide (ROR = 0.27, 95 % CI = 0.09-0.83) were associated with significantly lower reporting odds. All significant signals satisfied thresholds of p < 0.05 and IC> 0.. ConclusionsCertain GLP-1 receptor agonists demonstrate a pharmacovigilance signal of disproportionate reporting of muscle atrophy. These findings should be interpreted as signal detection rather than evidence of causality and highlight the need for future studies incorporating objective measures of muscle mass and function.. 25
