The authors find that the choice of target population is critical to the cost-utility of bisphosphonate treatment. If treatment is targeted towards individuals at high risk of fracture then both alendronate and etidronate appear to be reasonably cost-effective. However they cannot support the use of etidronate, as RCTs have not detected a reduction in non-vertebral fracture rate, despite suggestions from proxy measures that this may result. Alendronate is preferred, despite it being a more expensive drug, as the quality of evidence for its effectiveness is higher.