Outcomes
The primary outcome of this study was all-cause home oxygen cessation at three, six, nine, and twelve months corrected gestational age (CGA).  Time on oxygen was calculated from birth to CGA at oxygen cessation using CGA in days as a timescale.  Infants who did not achieve the outcome at 12 months CGA or those who were lost to follow up before the end of study (n=20) were censored.   
 
A secondary outcome was to assess maternal and infant predictors of home oxygen flow rate required at hospital discharge.  Another was to examine how oxygen flow rates at discharge predicted various post-discharge variables up to 24 months chronological age which included respiratory related emergency department (ED) presentations, respiratory related hospital admissions, doctor documented wheeze, prescribed oral corticosteroids, prescribed inhaled corticosteroids, pediatric intensive care unit (PICU) admissions, and pulmonary hypertension.