Table 5.

Subgroup analysis of the effect of rhEPO on confirmed NEC

	Control n/total (%)	rhEPO n/total (%)	p-value	Relative risk [95% CI]	Interaction p	Total n/total (%)
Gestation age
< 28 w	9/53 (17.0)	2/57 (3.5)	0.019	0.178 [0.037–0.865]		11/110 (10.0)
28–296/7 w	14/258 (5.4)	7/288 (2.4)	0.069	0.434 [0.172–1.093]		21/546 (3.8)
30–32 w	12/333 (3.6)	10/296 (3.4)	0.878	0.935 [0.398–2.198]	0.013	22/629 (3.5)
Birth weight
< 1000 g	12/54 (22.2)	2/50 (4.0)	0.007	0.146 [0.031–0.689]		14/104 (13.5)
1000–1499 g	19/432 (4.4)	10/462 (2.2)	0.060	0.481 [0.221–1.046]		29/894 (3.2)
≥ 1500 g	4/158 (2.5)	7/129 (5.4)	0.204	2.209 [0.632–7.720]	0.142	11/287 (3.8)
Delivery mode
Vaginal delivery	15/260 (5.8)	4/240 (1.7)	0.017	0.277 [0.091–0.846]		19/500 (3.8)
Caesarean	20/384 (5.2)	15/401 (3.7)	0.319	0.707 [0.357–1.402]	0.154	35/785 (4.5)
Gender
Girl	12/259 (4.6)	4/267 (1.5)	0.036	0.343 [0.108–1.091]		16/526 (3.0)
Boy	23/385 (6.0)	15/374 (4.0)	0.215	0.647 [0.332–1.260]	0.267	38/759 (5.0)
Mechanical ventilation
< 7 days	28/577 (4.9)	17/553 (3.1)	0.126	0.622 [0.336–1.149]		45/1130 (4.0)
≥ 7 days	7/67 (10.4)	2/88 (2.3)	0.031	0.199 [0.040–0.993]	0.181	9/155 (5.8)
1 min Apgar score
> 3	32/614 (5.2)	19/617 (3.1)	0.061	0.578 [0.324–1.031]		51/1231 (4.1)
≤ 3	3/30 (10.0)	0/24 (0.0)	0.111	0.900 [0.799–1.014]	0.226	3/54 (5.6)
5 min Apgar score
> 5	34/622 (5.5)	19/608 (3.1)	0.060	0.558 [0.315–0.989]		53/1230 (4.3)
≤ 5	1/22 (4.5)	0/33 (0.0)	0.400	0.389 [0.278–0.543]	0.053	1/55 (1.8)
Hemoglobin
≥ 90 g/l	11/296 (3.7)	7/301 (2.3)	0.320	0.617 [0.236–1.614]		18/597 (3.0)
< 90 g/l	24/348 (6.9)	12/340 (3.5)	0.047	0.494 [0.243–1.004]	0.715	36/688 (5.2)

Confirmed NEC means NEC stage II and III