Variable Hazard Ratio Standard error z-score P value 95% CI
BPD 0.12 0.09 -2.94 .003 0.03-0.49
Time on ventilator 0.19 0.05 -6.51 <.001 0.11-0.31
BPD*Time on ventilator 2.23 0.61 3.09 .002 1.35-3.84