Subgroup analyses
BPD, death, chorioamnionitis
REGRESSION, CHORIOAMNIONITIS
We plan to include a Kaplan–Meier curve of survival up to hospital discharge or 52 weeks’ PMA (whichever comes first). If requested by journal editors or reviewers, we may perform other analyses that are not mentioned in this protocol. These will be performed consistently with the principles of this analysis plan, as far as possible.We acknowledge that the trial is not powered for subgroup analyses and therefore the analyses listed in this section are considered exploratory.For the primary outcome subgroup analysis will be performed according to the pre-randomization strata: gestational age, exposure to surfactant prior to randomization, and mode of respiratory support at randomization. In addition, we plan to assess the effect of important factors that might modulate the risk of death and BPD, including sex, small for gestational age, and the presence of chorioamnionitis (Table Results of the subgroup analysisThe first step in the subgroup analysis will be to run a binomial regression (with stratification variables as covariates) with an interaction term between the subgroup variable and the treatment arm (Example Table Plot of the individual subgroup risk differences (95% CI) for the primary outcome