Statistical methods for the confirmative part
The modifying effect of a candidate variable will be illustrated by reporting the mean values of the outcomes in each treatment group within each subpopulation defined by the candidate variable directly or after a suitable categorization. Categorizations will aim at defining three to five groups of equal size.The estimated treatment effect at two anchor points will be visualized in a forest plot with 95% confidence intervals, and the modifying effect will be assessed as the difference between the effect at these two anchor points (interaction) with a 95% confidence interval and 