Table 1

General characteristics of population (SD) arranged according to different age groups

Group A
GA <28 weeks
Group B
GA ⩾28,
⩽32 weeks
Group C
GA >32,
<37 weeks
p Values Differences
between groups
Mean gestational age (weeks)26.9 (0.8)29.9 (1.0)34.4 (1.2)<0.00A-B-C
Mean birth weight (g)936 (144)1305 (298)2089 (438)<0.00A-B-C
Artificial ventilation (days)18.6 (12.7)7.1 (9.4)0.2 (0.8)<0.00A-B-C
Supplemental O2 (days)45.8 (35.8)37.9 (85.2)0.3 (0.8)<0.00(A=B)-C
Mean maximum O2administration (%)67.4 (28.2)66.2 (32.3)22.2 (3.0)<0.00(A=B)-C
Mean duration of hospitalisation (days)71.1(37.8)54.2 (60.1)22.3 (9.4)<0.00(A=B)-C
BPD (N (%))16 (50%)19 (29.7%)0<0.1(A=B)-C
PDA (N (%))14 (43.8%)13 (20.3%)0<0.02A-B-C
ROP (N (%))21 (65.6%)12 (18.7%)0<0.00A-B-C
  • Continuous variables were tested by ANOVA on class differences and p values are listed in column 5. A Tukey post hoc procedure was performed to determine which age groups are really different from each other. A χ2 test was performed on discrete variables Bronchopulmonary dysplasia (BPD), persistent ductus arteriosus (PDA), retinopathy of prematurity (ROP) of groups A and B.