Results may not be generalisable to the community

EDITOR—The hip protector trial reported by Meyer et al is methodologically a notable improvement on previous hip protector trials.1 However, some methodological shortcomings affect the study, and issues arise about its generalisability to people at high risk who are not resident in nursing homes.

An important problem, not noted by the authors, is that the study groups have differential loss to follow up. In the intervention group 64% of the participants completed the 18 month follow up compared with only 57% of the controls (P=0.04). This difference can introduce selection bias and could give a false estimate of effectiveness. In addition, there seems to be some evidence that the control group may have been frailer than the intervention group as the death rate was somewhat greater and this may have explained the higher incidence of falls in the control group. These differences could explain some of the apparent effectiveness of the hip protectors.

Interestingly, the compliance rate for the hip protectors was very low, at only 35%, not 68% as implied in the abstract. This low compliance rate is similar to that in our ongoing community study in which we simply post hip protectors to participants at high risk.

Finally, although these data may support the use of hip protectors among nursing home residents, evidence for their effectiveness among older people at high risk who are living in the community is still required. We are undertaking a large individually randomised trial among 4200 women at increased risk of hip fracture living in the community, the results of which will be reported this summer.