Table 4. Demographic data and clinical characteristics of infants with and without AKI.

	No AKI, n = 122	AKI, n = 154	p value
Infants’ demographic data
Gestational age (weeks)*	27 (26,28)	25 (24,26)	<0.001
Birth weight*	847 (741,915)	745 (662,832)	<0.001
Male gender	56 (46%)	88 (57%)	0.063
Cesarean section	98 (80%)	104 (68%)	0.015
Multiple birth	27 (22%)	43 (28%)	0.272
Apgar score at 1 minute*	5 (4,7)	4 (3,5)	<0.001
Apgar score at 5 minutes*	8 (7,9)	7 (6,8)	<0.001
1st arterial blood gas pH*	7.33 (7.27,7.39)	7.28 (7.18,7.36)	<0.001
Clinical intervention
Umbilical artery catheter	82 (67%)	121 (79%)	0.034
High frequency ventilator	51 (42%)	125 (81%)	<0.001
Gentamicin	88 (72%)	96 (62%)	0.087
NSAIDs	7 (6%)	15 (10%)	0.223
Inotropic agents	66 (54%)	132 (86%)	<0.001
Co-morbidity
Culture-proven bacteremia/fungemia	24 (20%)	34 (22%)	0.626
Intraventricular hemorrhage	25 (21%)	62 (40%)	0.001
Necrotizing enterocolitis, stage II/III	10 (8%)	6 (4%)	0.129
Patent ductus arteriosus	44 (36%)	118 (77%)	<0.001
Maternal clinical exposure
Diabetes	7 (6%)	2 (1%)	0.047
Hypertension	12 (10%)	6 (4%)	0.047
Pre-eclampsia	31 (25%)	11 (7%)	<0.001
Chorioamnionitis	10 (8%)	27 (18%)	0.024
Prenatal antibiotics	52 (43%)	85 (55%)	0.038
Prenatal steroids	83 (68%)	93 (60%)	0.190
Placental hemorrhage	10 (8%)	21 (14%)	0.155
Premature rupture of membranes	43 (35%)	51 (33%)	0.711

*presented as the median and interquartile range.