Statistical Analysis
Organ Dysfunction
REGRESSION, SECONDARY
Continuous data were reported as the mean and standard deviation (SD) or as the median and first quartile (Q1); third quartile (Q3) (Q1; Q3), as appropriate. Categorical data were reported as numbers and percentages. Data analyses were performed in R Statistical Software version 4.1.2 (R core team 2021). The complete reference list of the used R packages is shown in Method 1, Supplemental Digital Content 1, The primary outcome was the course of the biomarker concentrations during PICU stay. The course was studied only in patients with available biomarker concentrations on all days (admission, day 3, and day 5). The course was displayed in graphs, and the Friedman and (post hoc) Wilcoxon signed-rank tests were used to examine the statistical significance of differences in biomarker concentrations throughout PICU stay.The secondary outcome was the longitudinal association between the biomarker concentrations and ENA. To investigate this association, a 2-part mixed effects model was used. This model combines a mixed-effects logistic regression for the dichotomous outcome zero or positive EN intake and a linear mixed-effects sub-model for the natural logarithm of the positive EN intake measurements. For both sub-models, the random-effects structure was random intercepts. In the fixed-effects part of the linear mixed model, we included the main effects of the follow-up time variable, diagnostic group, Pediatric Logistic Organ Dysfunction (PELOD) score (As additional analyses, the differences in biomarker concentrations per day between patients with FIS and without FIS, and between patients in the early-PN and the late-PN group, were investigated using the Mann-Whitney 