Results
BPD, death, NDI
Among the 799 infants included in the analysis (421 boys [52.7%]), the mean (SD) gestational age was 24.9 (1.5) weeks, and the mean (SD) birth weight was 715 (167) g. The mean estimated baseline risk for grades 2 to 3 BPD or death was 54% (range, 18%-84%) in the study population. The interaction between treatment group and baseline risk was not statistically significant on a relative or absolute scale for grades 2 to 3 BPD or death; the size of the effect ranged from a relative risk of 1.13 (95% CI, 0.82-1.55) in quartile 1 to 0.94 (95% CI, 0.81-1.09) in quartile 4. Similarly, the interaction between treatment group and baseline risk was not significant on a relative or absolute scale for moderate or severe NDI or death; the size of the effect ranged from a relative risk of 1.04 (95% CI, 0.80-1.36) in quartile 1 to 0.99 (95% CI, 0.80-1.22) in quartile 4.