Table 3.

Linear Mixed Model – Clinical Characteristics and Outcome

Variable	Male	Female	p-value
LOS (days)	Gender	3.31	0.421
	GA	−5.16	0.000
	Z score	−6.12	0.079
	Order	2.08	0.616
O2 enrichment	Gender	2.08	0.536
	GA	−6.01	0.000
	Z score	−1.76	0.529
	Order	3.10	0.364
Invasive ventilation (days)	Gender	2.67	0.224
	GA	−5.03	0.000
	Z score	−0.21	0.928
	Order	1.84	0.498
Total ventilation (days)	Gender	1.22	0.531
	GA	−3.37	0.000
	Z score	−1.05	0.518
	Order	1.80	0.363
Apgar 1 min	Gender	0.06	0.756
	GA	0.49	0.000
	Z score	0.10	0.600
	Order	−0.26	0.197
Apgar 5 min	Gender	−0.03	0.746
	GA	0.34	0.000
	Z score	0.21	0.080
	Order	−0.08	0.455
PH	Gender	−0.17	0.204
	GA	0.04	0.218
	Z score	−0.10	0.257
	Order	−0.20	0.13

Estimate – the amount of change in the dependent variable for each increase of one unit in the independent variable. Estimate regarding gender – male versus female. Estimate regarding order – first born versus second born. Total ventilation (days) includes nasal CPAP and invasive ventilation. PH refers to levels in the umbilical cord

CPAP continuous positive airway pressure, GA gestational age, LOS length of stay (hospitalization days)