Primary Outcomes for Benchmark, Intervention, and Control Groups

OutcomeBenchmark Centers, Year 1Intervention CentersControl CentersP
%OR (95% CI)%OR (95% CI)
Year 1Year 3Year 1Year 3
Survival free of BPDa73.363.362.262.762.8.40 (.03)b
    Gestational age of <26 wk52.838.422.30.47 (0.27–0.82)31.729.50.84 (0.55–1.30).10
    Gestational age of ≥26 wk83.171.376.51.23 (0.88–1.71)75.375.91.00 (0.75–1.33).35
Survival to PMA of 36 wk84.485.384.20.96 (0.67–1.37)87.586.30.83 (0.60–1.14).56
BPD, physiologic definitiona13.425.726.128.327.2.13 (.01)b
    Gestational age of <26 wk24.037.660.72.53 (1.31–4.90)55.355.81.01 (0.63–1.63).03
    Gestational age of ≥26 wk9.523.118.70.80 (0.56–1.16) (0.70–1.33).47
BPD severitya0.81 (0.60–1.11)0.98 (0.76–1.28).36
  • Benchmark center data were collected from October 2000 to May 2001. All analyses compared the differences in the changes between study year 1 and year 3 in the intervention centers, compared with the control centers. Variables included in the model were group assignment (intervention versus control), study year, group-study year, birth weight, gender, race, prenatal steroid exposure, interaction with gestational age of <26 weeks, and random clustering effect according to center.

  • a BPD severity was defined with a modification of the National Institutes of Health consensus definition of BPD that included results of a timed room air challenge (see “Methods”). For this analysis, BPD severity was dichotomized as any BPD versus no BPD.

  • b Analyses that demonstrated effect modification by gestational age are shown with overall results and with results according to gestational age group. The significance of interaction term is shown in parentheses.