Differential Biliary Adverse Event Signals Among Glp-1 Receptor Agonists: A FAERS Disproportionality Analysis.

This pharmacovigilance study analyzed reports submitted to the FDA Adverse Event Reporting System (FAERS) to compare biliary adverse events (AEs) across five GLP-1 receptor agonists (GLP-1RAs): semaglutide, tirzepatide, liraglutide, exenatide, and dulaglutide. After deduplication, 3,460 reports were included. Using semaglutide as the reference, the authors calculated proportional reporting ratios (PRR), reporting odds ratios (ROR), and Fisher exact tests across five biliary outcomes: cholelithiasis, cholecystitis, biliary colic, bile duct stone, and cholangitis. The study found that compared with semaglutide, exenatide and tirzepatide showed lower relative reporting for bile duct stone, while exenatide and dulaglutide showed lower relative reporting for biliary colic. Dulaglutide showed higher relative reporting for cholangitis. Exenatide, liraglutide, and tirzepatide all showed higher relative reporting for cholecystitis and cholelithiasis. Sensitivity and subgroup analyses were broadly consistent, though rarer outcomes lost statistical significance. Key limitations include the inherent biases of spontaneous reporting databases (underreporting, confounding by indication, and lack of denominator data), which preclude causal inference. The authors concluded that biliary AE reporting patterns differ meaningfully across agents within the GLP-1RA class.

Why this grade: Disproportionality analyses of spontaneous pharmacovigilance databases (FAERS) are hypothesis-generating only; they cannot establish causation, lack true denominators, and are subject to substantial reporting biases, limiting the strength of any human evidence claim.