Preliminary analysis for the ADD-BP study: Atypical femoral fractures and physical activity levels in bisphosphonate users

OBJECTIVE: To investigate the relationship between physical activity levels and atypical femoral fractures (AFF) in bisphosphonate (BP) users. METHODS: In the Assessing Daily-Activity-Level for Decisions on Bisphosphonate Prescription (ADD-BP) study, we retrospectively analyzed 27 women with AFF from five hospitals (2019-2023), categorized into BP (n = 18) and no-BP (n = 9) groups. Pre-injury physical activity was assessed via mobility aid usage, Long-Term Care Insurance System status, and independence in daily living. RESULTS: Median ages were 77 years (BP) and 86 years (no-BP). In the BP vs. no-BP groups, 83.3% vs. 33.3% used no mobility aids, 11.1% vs. 22.2% used canes, and 5.6% vs. 33.3% used walkers. No BP users (0%) vs. 33.0% of no-BP users were housebound ; others were independent. CONCLUSION: BP users with AFF exhibited higher physical activity levels than non-users, suggesting low activity may not elevate AFF risk in long-term BP use. These findings support the safety of extended BP therapy for fragility fracture prevention in less active patients. Future case-control studies are needed to confirm these results. This study was approved by the Fukushima Medical University Ethics Committee (REC2023-176).