Fractures due to Aromatase Inhibitor Therapy for Breast Cancer: A Real-World Analysis of FAERS Data in the Past 15 Years

INTRODUCTION: The adverse effect of fractures by different aromatase inhibitor (AI) drugs has not been thoroughly assessed in real-world studies. OBJECTIVE: To assess the adverse events of fractures of real-world breast cancer patients caused by AI therapy through the Food and Drug Administration Adverse Event Reporting System (FAERS) database. METHODS: The FAERS data from January 2004 to December 2018 were sorted out and analyzed for correlations between fractures and AI use. Disproportionate analysis and Bayesian analysis were adopted to quantify the signal, the association between the AIs and fractures. The onset time and outcome of fractures after different AI regimens were also compared. RESULTS: Out of 23,064 adverse reports, 657 fracture reports (2.85%) were analyzed. Anastrozole showed a positive association with 4 detection methods, while letrozole and exemestane did so with 2. More exemestane-related reports (44.62%) resulted in initial or prolonged hospitalization than anastrozole (30.12%, p = 0.013) and letrozole (29.43%, p = 0.006). The fracture onset time showed no significant difference among anastrozole, letrozole, and exemestane (median onset time: 46.95, 34.25, and 40.58 months, respectively; p = 0.236). CONCLUSIONS: Anastrozole should be prescribed with more medical care. Analysis of FAERS data identified fracture risk tendencies with AI regimens, which supported continuous monitoring, risk evaluations, and further comparative studies.