Grant: Operating Grant

Osteoporosis is a common disease, characterized by low bone mass and increased fracture risk. Osteoporosis and fractures are responsible for lasting disability, morbidity and excess mortality. Individuals who sustain an osteoporosis-related fracture are also at high risk of recurrent fracture. In 1990, approximately 1.7 million incident hip fractures (the most serious fracture associated with osteoporosis) occurred worldwide and this number is expected to rise to 2.6 million by 2025. In Canada, there were 30,000 hip fractures in 2005. In Canada, the costs associated with the treatment of hip fractures are expected to rise to $2.4 billion by 2041. Bisphosphonates (such as alendronate and risedronate) are the pharmacological agents most frequently prescribed to treat individuals with osteoporosis. They have been shown to reduce the risk for fractures in many clinical trials in patients who have sustained fractures and in those with a low bone density. Bisphosphonates are usually well tolerated. However, there have been recent reports that long-term use of these agents in older adults might be associated with rare, specific type of fractures of the femur called subtrochanteric and diaphyseal fractures. These reports bring into question the long-term safety of the bisphosphonates and have has raised concerns in primary health care professionals and in patients alike. Using administrative healthcare information collected in the Province of Québec by the Régie de Assurance-Maladie du Québec, we propose to study the risk of developing these unusual fractures following exposure to bisphosphonate therapy. We also wish to study the effectiveness of these medications in older patients who have sustained a hip fracture and are at very high risk for recurrent fractures. It is important to evaluate the benefits and thepotential long-term adverse effects of medications used to treat osteoporosis so to better guide therapeutic decision making.