Statistical analysis
infection, infections
REGRESSION, INFECTION, RECRUITMENT, INFECTIONS
Statistical analyses followed the statistical and health economic analysis planThe co-primary outcome SSI was analysed using logistic regression, adjusting for recruitment site as the only stratification factor using the cluster robust option in StataThe cost-effectiveness analysis took a time horizon of up to 12 months and estimated the cost per infection avoided, using the primary outcome measure from the trial (infections at 7 days). The cost of operating time was included. Further information about the cost-effectiveness analysis is provided in the statistical and health economic analysis plan, and detailed methods and results of the economic evaluation will be reported separately. Confidence intervals were estimated using bootstrapping and included multiple imputation of missing data. Cost is presented in Euros based on an exchange rate of 1 GBP = 1.126 EUR on 8th February 2023.