Table 2.

Heterogeneity test and meta-analysis results of NEC risk factors in premature infants

Research factors	Number of studies	Heterogeneity test			Effect model	Pooled OR (95%CI)	Pooled p value
		Q	I2 (%)	P
Septicemia	25	43.43	45	0.009	Fixed effect	3.91 (3.37, 4.55)	< 0.001
Blood transfusion	13	23.68	49	0.02	Fixed effect	2.41 (1.97, 2.95)	< 0.001
Neonatal asphyxia	14	23.58	45	0.04	Fixed effect	2.46 (2.07, 2.93)	< 0.001
Pneumonia	6	1.34	0	0.93	Fixed effect	6.17 (3.98, 9.57)	< 0.001
Infection occurs	2	1.43	30	0.23	Fixed effect	5.99 (2.57, 13.93)	< 0.001
Oral probiotics	17	96.90	83	< 0.001	Random effect	0.36 (0.25, 0.53)	< 0.001
Breastfeeding	13	302.01	96	< 0.001	Random effect	0.31 (0.16, 0.62)	< 0.001
Congenital heart disease	3	2.01	1	0.37	Fixed effect	4.80 (3.00, 7.68)	< 0.001
Intrahepatic cholestasis of pregnancy	4	2.17	0	0.54	Fixed effect	2.71 (1.92, 3.82)	< 0.001
Mechanical ventilation	4	0.68	0	0.88	Fixed effect	1.44 (1.22, 1.71)	< 0.001
Gestational diabetes	2	0.06	0	0.80	Fixed effect	3.08 (1.73, 5.48)	0.0001
Respiratory distress syndrome	4	1.24	0	0.74	Fixed effect	3.28 (2.23, 4.85)	< 0.001
Prenatal application of glucocorticoids	5	6.19	35	0.19	Fixed effect	0.38 (0.24, 0.60)	< 0.001
Intravenous Immunoglobulin	2	5.46	82	0.02	Random effect	0.70 (0.10, 5.20)	0.73
Hypoalbuminemia	2	0.43	0	0.51	Fixed effect	2.80 (1.78, 4.41)	< 0.001
Patent ductus arteriosus	3	0.28	0	0.87	Fixed effect	3.10 (1.93, 4.98)	< 0.001
respiratory failure	2	3.50	71	0.06	Random effect	7.51 (1.60, 35.10)	0.01
Severe anemia	4	2.02	0	0.57	Fixed effect	2.86 (2.06, 3.99)	< 0.001
History of antibiotic use	2	4.53	78	0.03	Random effect	2.12 (1.18, 3.81)	0.01
Meconium-stained amniotic fluid	2	0.05	0	0.82	Fixed effect	3.14 (1.64, 6.01)	< 0.001