Effects of beta-blockers on fracture risk.

Laboratory studies make clear that the sympathetic nervous system does impact on bone cell and tissue function. However, these effects are inconsistent between models, possibly reflecting sympathetic effects at different levels, from the central nervous system through to the bone cells. Observational studies of the use of beta-blockers are confounded by the indications for which these drugs are prescribed, and by other medications that are commonly co-prescribed with them. These data are inconsistent, although a recent meta-analysis did conclude that beta-blocker use was associated with a significant decrease in fracture risk. However, the more recent studies cast doubt on this finding, and the limited data regarding fractures in randomized controlled trials certainly do not support this conclusion. Therefore, there is not an adequate evidence base to support using beta-blockers as a treatment for osteoporosis, nor can they be regarded as a discriminating risk factor for fracture assessment. Until there are definitive randomized, controlled trials of beta-blockers, which include fracture as an endpoint, it is unlikely that the current confusing situation will be resolved.