Proton Pump Inhibitor Use and the Antifracture Efficacy of Alendronate

BACKGROUND: Proton pump inhibitors (PPIs) are widely used in elderly patients and are frequently coadministered in users of oral bisphosphonates. Biologically, PPIs could affect the absorption of calcium, vitamin B(12), and bisphosphonates and could affect the osteoclast proton pump, thus interacting with bisphosphonate antifracture efficacy. Moreover, PPIs themselves have been linked to osteoporotic fractures. METHODS: Population-based, national register-based, open cohort study of 38 088 new alendronate sodium users with a mean duration of follow-up of 3.5 years. We related risk of hip fracture to recent pharmacy records of refill of prescriptions for alendronate. RESULTS: For hip fractures, there was statistically significant interaction with alendronate for PPI use (P