Table 4 Univariate analysis of the clinical outcomes of VPIs among the three groups

NEC ≥ stage2, n(%)

1 (0.7)

6 (1.6)

85 (6.5)^a,b

21.229

<0.001

HAI, n(%)

11 (7.2)

42 (11.2)^a

180 (13.8)^a

6.148

0.046

hsPDA, n(%)

6 (3.9)

24 (6.4)

219 (16.7)^a,b

39.527

<0.001

IVH (grade 3 or 4), n(%)

1 (0.7)

3 (0.8)

22 (1.7)

2.295

0.317

PVL, n(%)

2 (1.3)

13 (3.5)

38 (2.9)

2.108

0.349

Moderate and severe BPD, n(%)

3 (2.0)

30 (8.0)^a

147 (11.2)^a

14.913

0.001

PNAC, n(%)

4 (2.6)

15 (4.0)

112 (8.6)^a,b

14.171

0.001

ROP requiring intervention, n(%)

2 (1.3)

3 (0.8)

34 (2.6)

5.037

0.081