Atypical Femur Fracture Risk versus Fragility Fracture Prevention with Bisphosphonates.
Black DM, Geiger EJ, Eastell R, et al. The New England journal of medicine 2020 · PMID 32813950 · doi:10.1056/nejmoa1916525
- Question
- How does the risk of atypical femoral fracture relate to bisphosphonate duration, ethnicity and stopping treatment, and how does it compare with fractures prevented?
- Design
- Large retrospective cohort study in a US integrated healthcare system (Kaiser Permanente Southern California) with radiographic adjudication of fractures.
- Patients
- Around 200,000 women aged 50 and over treated with bisphosphonates.
- Intervention
- Bisphosphonate exposure by duration
- Comparison
- Shorter or no exposure; time since stopping
- Primary outcome
- Adjudicated atypical femoral fracture
- Key result
- Atypical femoral fracture risk rose with longer bisphosphonate use, was substantially higher in Asian women, and fell rapidly after stopping; in white women the hip and other fractures prevented far exceeded the atypical fractures caused.
- Limitations
- Observational design with possible residual confounding; single US health system may limit generalisability to UK populations.
- Impact on practice
- Supports reassessment and consideration of a drug holiday after several years of bisphosphonate therapy in lower-risk patients, as in NOGG, and vigilance for prodromal thigh pain in long-term users and Asian women.