Clinical characteristics and risk factors of very low birth weight and extremely low birth weight infants with bronchopulmonary dysplasia: multicenter retrospective analysis

Abstract

Objective: To analyze clinical characteristics and risk factors of very low birth weight and extremely low birth weight infants with bronchopulmonary dysplasia (BPD). Methods: A retrospective epidemiological study was performed in 768 neonates (376 males) with birth weights<1 500 g and gestational age ≤ 34 weeks who survived ≥28 days. Clinical data were obtained from the multi-center clinical database of neonatal intensive care units (NICU) in 19 hospitals of Jiangsu Province between January 1, 2017 and December 31, 2017. These infants were divided into non-BPD group and BPD group according to BPD diagnositic criteria. Clinical features and potential risk factors were compared between groups with Chi-square test or nonparametric test. Risk factors for BPD were analyzed with Logistic regression analysis. Results: Among the total of 768 eligible neonates, 577 without BPD, 191 with BPD (24.9%). Mild, moderate and severe BPD accounted for 73.3% (140/191), 23.6% (45/191) and 3.1% (6/191) of all BPD cases respectively. There were significant differences in the average gestational age (29 (28, 30) vs. 30 (29, 31) weeks) or the average birth weight (1 170 (990, 1 300) vs. 1 300 (1 160, 1 400) g) between BPD group and non-BPD group (Z=-9.959,-7.202, both P=0.000). The incidences of BPD in the infants with gestational age of<28 weeks, 28-31 weeks and 32-34 weeks were 51.7% (46/89), 24.8% (139/561), 5.1% (6/118) respectively. The incidences of BPD in infants with birth weight<1 000 g, 1 000- 1 249 g and 1 250-1 500 g were 62.3% (48/77), 25.9% (70/270) and 17.3% (73/421) respectively. Proportion of male (55.5% (106/191) vs. 46.8% (270/577)), rate and length of conventional mechanical ventilation (48.7% (93/191) vs. 14.9% (86/577), 120 (72, 259) vs. 80 (29, 144)h), initial inhaled oxygen concentration and maximum inhaled oxygen concentration (0.35 (0.30, 0.40) vs. 0.30(0.25, 0.40), 0.40 (0.30, 0.50) vs. 0.30 (0.30, 0.40)) and volume of red blood cell transfusion (53(30, 90) vs.38(28, 55) ml) were higher in BPD group than in non-BPD group (χ(2)=4.350, 91.640, Z=-3.557, -2.848, -3.776, -4.677, all P<0.05). Rate of continuous positive airway pressure (12.6%(24/191) vs. 19.4%(112/577)) during neonatal resuscitation in delivery room was lower in BPD group than that in non-BPD group (χ(2)=4.614, P=0.032). The incidences of complications in BPD group including severe asphyxia, neonatal respiratory distress syndrome (NRDS), persistent pulmonary hypertension in newborns (PPHN), patent ductus arteriosus, anemia of prematurity, early onset sepsis, clinical sepsis and ventilator associated pneumonia were higher than that in non-BPD group (15.2%(29/191) vs. 4.5% (26/577), 91.1% (174/191) vs. 56.7% (327/577), 2.6% (5/191) vs. 0.2% (1/577), 43.5% (83/191) vs. 34.2% (197/577), 88.0% (168/191) vs. 58.8% (339/577), 15.7% (30/191) vs. 9.9% (57/577), 42.9% (82/191) vs. 18.6% (107/577), 14.1% (27/191) vs. 2.3% (13/577); χ(2)=24.605, 74.993, 9.167, 5.373, 61.866, 4.557, 43.149, 34.315, all P<0.05). Multivariate logistic regression analysis showed that NRDS (OR=4.651, 95%CI: 1.860-11.625), clinical sepsis (OR=1.989, 95%CI: 1.067-3.708), ventilator associated pneumonia (OR=3.155, 95%CI: 1.060-9.388), conventional mechanical ventilation (OR=2.298, 95%CI: 1.152-4.586), and volume of red blood cell transfusion (OR=1.013, 95%CI: 1.002-1.024) were risk factors of BPD. Conclusions: BPD is more common in very low birth weight infants of male with gestational age less than 32 weeks. Using CPAP in the delivery room, active treatment of NRDS, preventing nosocomial infection, and reducing invasive ventilation and red blood cell transfusion may decrease the incidence of BPD.