. 2018 Apr 2;18:83. doi: 10.1186/s12886-018-0732-3

Table 3.

Risk factor for retinopathy of prematurity in Iran

Variables	Studies(N^a)	Sample (N)		Heterogeneity		OR (95%CI^b)	P-Value	Model in Meta-analysis
Variables	Studies(N^a)	Case	Control	I²	P-Value	OR (95%CI^b)	P-Value	Model in Meta-analysis
Twin birth	4	804	1868	46.97	0.129	1.62 (0.94 to 2.81)	0.081	Random^c
Mechanical ventilation	6	1131	2493	73.35	0.002	1.81 (0.80 to 1.73)	0.39	Random
Continuous positive pressure ventilation	2	62	131	64.11	0.095	3.97 (1.21 to 13.01)	0.023	Random
Blood transfusion (N)	16	1820	4167	91.34	< 0.001	2.38 (1.43 to 3.94)	0.001	Random
Septicemia	11	1327	2965	80.75	< 0.001	1.96 (1.10 to 3.48)	0.021	Random
Birth weight < 1000 g	9	573	2093	59.65	0.011	4.16 (2.35 to 7.35)	< 0.001	Random
Birth weight < 1500 g	10	559	1984	43.34	0.069	3.74 (2.54 to 5.49)	< 0.001	Random
Phototherapy (N)	11	1380	3355	80.69	< 0.001	1.50 (1.00 to 2.27)	0.049	Random
Oxygen therapy (N)	14	726	3124	87.39	< 0.001	3.06 (1.29 to 7.27)	0.011	Random
Need for resuscitation	2	56	212	86.50	0.006	5.01 (0.18 to 135.71)	0.338	Random
Apnea	3	114	492	72.08	0.028	4.41 (1.70 to 11.40)	0.002	Random
Congenital heart disease	2	50	246	67.29	0.08	2.13 (0.10 to 45.62)	0.626	Random
Inter-ventricular hemorrhage	11	1223	3178	76.36	< 0.001	2.24 (1.2 to 3.95)	0.005	Random
Acidosis	3	132	296	62.62	0.069	2.56 (0.81 to 8.06)	0.106	Random
Cesarean section	4	375	830	47.88	0.124	1.08 (0.53 to 2.18)	0.82	Random
Preeclampsia	2	108	237	0	0.82	0.12 (0.02 to 0.65)	0.014	Fixed^d
Respiratory distress syndrome	11	2039	2618	80.13	< 0.001	1.64 (1.03 to 2.61)	0.036	Random
Saturation above 50%	4	118	656	30.30	0.23	8.35 (3.14 to 22.18)	< 0.001	Random
Normal Vaginal Delivery	4	375	830	46.63	0.132	1.01 (0.50 to 2.02)	0.969	Random
Multiple pregnancy	6	1199	2518	40.20	0.137	0.92 (0.73 to 1.16)	0.517	Random
Gestational age ≤ 28	6	551	1440	75.88	< 0.001	5.20 (2.31 to 11.73)	< 0.001	Random
Gestational age ≤ 32	9	689	1885	64.84	0.004	7.88 (4.62 to 13.46)	< 0.001	Random
Birth weight (gr)	7	1495	2893	97.30	< 0.001	0.98 (0.97 to 0.99)	< 0.001	Random
Gestational age (week)	7	1495	2893	84.20	< 0.001	0.67 (0.59 to 0.770)	< 0.001	Random
Variables	Studies(N^a)	Sample (N)		Heterogeneity		Mean Difference (95% CI^b)	P-Value
Variables	Studies(N^a)	Case	Control	I²	P-Value	Mean Difference (95% CI^b)	P-Value
Gestational age (weeks)	18	1835	4126	94.53	< 0.001	2.08(1.50 to 2.66)	< 0.001	Random
Birth weight (gr)	19	1782	4519	95.94	< 0.001	305.39(236.09 to 374.69)	< 0.001	Random
Oxygen therapy (day)	11	1399	3214	96.04	< 0.001	−4.36(−6.09 to −2.63)	< 0.001	Random
Phototherapy (days)	4	78	308	83.80	< 0.001	−2.08(−3.81 to −0.35)	< 0.001	Random
Apgar score in the first minute	3	174	216	63.30	0.66	1.07(0.45 to 1.68)	0.001	Random
Apgar score	3	64	272	76.34	0.015	0.43(−0.25 to −1.13)	0.21	Random
Mechanical ventilation (days)	2	114	154	88.81	0.003	−4.53(−9.17 to 0.10)	0.55	Random
Bilirubin (mg/di)	3	54	186	7.70	0.33	−0.27(−1.40 to 0.86)	0.63	Random
Blood transfusion (duration)	2	98	151	0	0.98	−0.69(−0.96 to − 0.42)	< 0.001	Fixed
clinical risk index for babies	2	161	250	58.84	0.11	−0.62(− 1.40 to 0.16)	0.11	Random

^aNumber

^bConfidence interval

^cRandom effects model

^dFixed effects model