Table 5.

Risk factors for 30-day mortality (67 deaths) in univariable and multivariable logistic regression analyses

	Univariable analysis		Multivariable analysis*
	Odds ratio	P	Odds ratio	P
Vaginal birth	1.05 (0.51, 2.17)	0.100
Gestational age at birth	0.98 (0.89, 1.07)	0.596
Birthweight per 50 g	1.00 (0.87, 1.15)	0.958
Male sex	1.55 (0.79, 3.03)	0.200	1.39 (0.69, 2.77)	0.355
IVH ≥ grade II with infarction	1.78 (0.60, 5.31)	0.298
Postnatal age at NEC diagnosis	0.98 (0.96, 1.00)	0.100	0.99 (0.96, 1.02)	0.471
CV support between NEC diagnosis and surgery	1.69 (0.87, 3.30)	0.121	1.52 (0.76, 3.03)	0.232
Pneumoperitoneum on radiological imaging	1.67 (0.86, 3.24)	0.131	1.37 (0.64, 2.94)	0.415
Year of first NEC surgery	1.04 (0.96, 1.13)	0.365	1.02 (0.94, 1.11)	0.696

Values in parentheses are 95% confidence intervals. IVH, intraventricular haemorrhage; NEC, necrotizing enterocolitis; CV, cardiovascular. *Risk factors with P ≤ 0.250 in univariable logistic regression analysis were included in the multivariable model, supplemented with the year of first NEC surgery.