2.5. Statistical Analysis
INTRAVENTRICULAR HEMORRHAGE
Statistical analysis was performed on the intention-to-treat analysis set (all randomized patients were included), with the exclusion of subjects that were lost for follow-up, moved, no dietary records or withdrawn informed consent. As the number of participants in this analysis was smaller compared to the initial randomized dataset, baseline characteristics and dietary intakes are reported from all participants valid for the analysis of the defined primary outcome, i.e., all subjects in which at least one 3-day dietary record and Bayley-III outcome assessment at 12 months CA was available. In the following, we defined this dataset as “PUFA subgroup”. For ordinal and nominal variables, absolute and relative frequencies are reported and continuous variables are presented using median and interquartile range (IQR). The primary outcome was assessed using linear mixed-effects models with PUFA intake, gestational age at birth, intervention group, sex, highest parental education, nutrition at discharge (breastfed, formula, mixed (breastmilk and formula), and intraventricular hemorrhage (Grades III + IV)) as fixed effects, and a random intercept to adjust for possible correlation between siblings of multiple births. Model estimates and 95% confidence intervals are reported. Secondary outcomes were assessed in the same manner as the primary outcome. As an additional analysis, 