Class-Wide Impaired Gastric Emptying Signal Across Nine GLP-1 Receptor Agonist Agents: Indication-Stratified Pharmacovigilance Analysis of 6,868 Cases in FDA FAERS (2004-2024) with Cross-National Validation

This large pharmacovigilance study analyzed 20.3 million FDA FAERS adverse event reports (2004–2024) to investigate impaired gastric emptying (IGE) as a potential class-wide adverse effect of GLP-1 receptor agonists (GLP-1 RAs). Researchers identified 6,868 IGE reports across nine GLP-1 RA agents and applied the proportional reporting ratio (PRR) method with sensitivity analyses, supplemented by cross-national validation using 29 reports from Brazil's pharmacovigilance database. The study found that all nine agents exceeded established Evans signal detection criteria, with PRRs ranging from 4.4 (exenatide) to 83.9 (injectable semaglutide). Notably, oral and injectable semaglutide showed comparable PRRs, suggesting a systemic rather than route-dependent mechanism. Tirzepatide prescribed for type 2 diabetes showed a substantially higher PRR than the same drug prescribed for obesity, which the authors interpret as a possible effect of diabetic autonomic neuropathy. A pre-litigation signal analysis was also conducted to account for potential notoriety bias. Key limitations include the inherent constraints of spontaneous pharmacovigilance data—including reporting bias, lack of denominator data, and inability to establish causation—as well as the small cross-national validation sample (n=29). The authors conclude that findings support pre-treatment risk stratification discussions for gastroparesis in GLP-1 RA candidates.

Why this grade: While the dataset is large and human-derived, the study relies entirely on spontaneous adverse event reporting (FAERS), which cannot establish causation, is subject to reporting and notoriety biases, and lacks a true denominator; it has not yet undergone peer review as a preprint.