Table 1:

Summary of studies Included in the meta-analysis by Garg et al.

Authors of study	Type of study	Gestational age	Birth weight	No. of infants case	No. of infants control	Hematocrit NEC	Odds ratio (OR, 95% confidence interval) RBC transfusion
Patel et al.	Case control	27.9 ± 3.3	1015 ± 273	40	554		For transfusion-0.4 (0.17–1.1), for anemia-5.9 (2–18; p = 0.001)
AlFelah et al.	Retrospective case control	28	1,042	40	112		OR = 0.39, (0.18–0.84), p = 0.02
Sharma et al.	Case control	27 ± 2	983 ± 333	42	42		1.4 (0.4–5.6)
Wallenstein et al.	Retrospective cohort	27 IQR 3	790 IQR 290	24	390	29	0.6 (0.2–1.7)
Bak et al.	Retrospective case control	27.6 ± 2.2	1027 ± 343	18	162	46.9 ± 4.1	1.63 (1.14–2.3)
Gomez-Martin	Retrospective case-control			30	30		1.5 (1.0–2.2)
Wan-Huen et al.	Case control	26 ± 2.4	840	49	97	31.4 ± 3.7	3.0 (1.7–5.5)
Demirel et al.	Case control	28.4 ± 1.4	1078 ± 236	96	551	30 ± 4.4	OR not mentioned
Stritzke et al.	Case control	25.8 ± 2.6	885 ± 446	927	2,781	NA	2.2 (1.8 0 2.8)
El-Dib et al.	Phase 1: Retrospective case-control; Phase 2: comparison study of incidence of NEC	26.8 ± 2.5	935 ± 350	25	25	NA	5.1 (1.4–17.9)
Paul et al.	Case control	26.8 ± 2.4	969 ± 239	33	30	28.6 ± 5.2	2.5 (0.8–8.3)
Singh et al.	Case control	26.9 ± 2.5	969.7 ± 309.0	111	222	29.9 ± 5.6	5.6 (3.2–10.2)
Christensen et al.	Retrospective case control	27 (26–28)	981 (835–1,128)	62	248	Not mentioned	11.8 (4.6–30.4)
Josephson et al.	Case control	27.7 (25.7–30.7)	1030 (740–1,410)	93	91	31.8 ± 7.8	0.7 (0.4–1.3)
Binder et al.			<1,500	78	783		0.07 (0.03–0.14)
Harsono et al.			<1,500	43	2,080		0.3 (0.2–0.6)
Garg et al.	Retrospective cohort	27.3 ± 2.5	992 ± 377	99		27.4 ± 4.5	2.83 (0.97–8.9)

NEC, necrotizing enterocolitis; RBC, red blood cell; IQR, interquartile range; NA, not applicable