The primary statistical analysis will be carried out on the basis of intention-to-treat (ITT). We will endeavour to obtain full follow-up data on every participant to allow full ITT analysis, but we will inevitably experience the problem of missing data due to withdrawal, loss to follow-up or non-response to some questionnaire items. The results from the trial will be prepared as compara- tive summary statistics with 95% CIs. All the tests will be performed at a 5% two-sided significance level. The study results will be reported in accordance with the Consoli- dated Standards of Reporting Trials guidelines.50 A full detailed statistical analysis plan will be prepared and final- ised before data collection is complete.