@article{ref1,
title="The impact of adherence on sports injury prevention effect estimates in randomised controlled trials: Looking beyond the CONSORT statement",
journal="Journal of science and medicine in sport",
year="2011",
author="Verhagen, Evert A. L. M. and Hupperets, Maarten D. W. and Finch, Caroline F. and Van Mechelen, Willem",
volume="14",
number="4",
pages="287-292",
abstract="Objective: To investigate estimated outcome effects of a sports injury prevention intervention when analysed by means of a per protocol (PP) analysis approach. Design: Randomised controlled trial (RCT) involving 522 athletes who sustained a lateral ankle sprain allocated to either an intervention (received a preventive programme in addition to usual care) or control group who were followed prospectively for one year. Methods: Secondary analysis of data relating to registered ankle sprain recurrences, exposure and adherence to the allocated intervention using a PP analysis approach. Results: Twenty-three percent of the RCT intervention group indicated to have fully adhered with the neuromuscular training programme. A per protocol analysis only considering fully adherent athletes and control athletes, showed a Hazard Ratio of 0.18 (95% CI: 0.07-0.43). Significantly fewer recurrent ankle sprains were found in the fully adherent group compared to the group that was not adherent (relative risk=0.63; 95% CI: 0.43-0.99). Conclusions: A PP analysis on fully adherent athletes versus control group athletes showed that the established intervention effect was over threefold higher compared to an earlier intention-to-treat based analysis approach. This shows that outcomes of intervention studies are heavily biased by adherence to the allocated intervention.<p /> <p>Language: en</p>",
language="en",
issn="1440-2440",
doi="10.1016/j.jsams.2011.02.007",
url="http://dx.doi.org/10.1016/j.jsams.2011.02.007"
}