- Kenneth E Poole, University lecturer, honorary consultant rheumatologist1,
- Juliet E Compston, professor of bone medicine 2
- 1Cambridge University Hospitals NHS Foundation Trust, Department of Medicine, Cambridge, UK
- 2Department of Medicine, University of Cambridge School of Clinical Medicine, Box 157, Addenbrooke’s Hospital, CB2 2QQ, UK
- Correspondence to: J E Compston
A 74 year old woman is admitted to hospital with a subtrochanteric hip fracture after a fall in her home. The T score for the bone mineral density (BMD) in her femoral neck is −3.2. She had a wrist fracture seven years ago but is otherwise healthy. Her 10 year absolute risk of any major osteoporotic fracture is 23% (calculated with the online WHO FRAX tool, www.shef.ac.uk/FRAX). The patient is treated surgically with internal fixation of the fracture. She is advised that she has a high risk of having further fractures, and the benefits and risks of possible treatment options to reduce this risk are discussed using a decision aid (http://musculoskeletal.cochrane.org/decision-aids). It is agreed that she will take alendronate, 70 mg once weekly for five years.
What are bisphosphonates?
Bisphosphonates are analogues of inorganic pyrophosphate. They inhibit bone resorption by inducing apoptosis of osteoclasts,1 thus preventing age related bone loss and deterioration of bone microarchitecture. Bisphosphonates that contain nitrogen (such as alendronate, risedronate, ibandronate, and zoledronic acid) have the most potent antiresorptive properties and are the most commonly used drugs in the treatment of osteoporosis. The bisphosphonate etidronate does not contain nitrogen, and although it is approved for treatment of postmenopausal osteoporosis, the evidence base is weaker and it is rarely prescribed nowadays.
How well do bisphosphonates work?
Large phase III randomised controlled trials in postmenopausal women with osteoporosis have shown significant reduction in vertebral fractures after three years of treatment with alendronate,2 risedronate,3 4 ibandronate,5 and zoledronic acid,6 and in non-vertebral fractures and hip fractures with alendronate,2 risedronate,7 and zoledronic acid.6 In the Fracture Intervention Trial, the incidence of vertebral fracture in women treated for three years with alendronate 5 mg daily for 24 months followed by 10 mg daily for 12 months was 8%, compared with 15% in …