Endocrine Abstracts

With the recent publication of the results of randomised controlled trials (RCTs) of HRT we are at last developing the potential to assess the relative safety as well as the relative efficacy of preventative treatment. As detailed on the website of the Medicines Control Agency (www.mca.gov.uk), treatment with HRT is associated with an increased risk of cancer of the breast and ovary, of stroke and venous thromboembolism, together with an increased rate of surgery for gallstones and of menstrual bleeding.
With respect to efficacy, conclusions should optimally be drawn from direct comparisons of the various medications. For the most part these comparisons are lacking. At the time of writing, the most comprehensive analysis of the efficacy of treatments to prevent or treat osteoporosis is contained in the Systematic Reviews of Randomised Trials in Osteoporosis, published in Endocrine Reviews 2002, 23: 496-507. It is not possible to summarise this rich publication within the confines of a short abstract. The absolute benefit of treatment is however most readily captured by determining the number of patients needed to treat (NNT) in order to prevent a single fracture. For vertebral fracture, for the most effective remedy (alendronate), the NNT over two years for a population at low risk of fracture was 1790 patients, for a population at high risk it was 72 patients. To prevent a single non vertebral fracture, the corresponding figure for a population at high risk was 24. Reliable equivalent figures for HRT are not available but HRT does have a consistent positive effect on bone mineral density, an important surrogate of fracture risk. While HRT may therefore retain a place in the prevention of osteoporotic fracture it is likely to be severely limited because of its concerning profile of adverse effects and the commanding efficacy of alternative remedies.