A comparison of the clinical diagnosis and outcome in preterm infants with bronchopulmonary dysplasia under two different diagnostic criteria

Abstract

Objective: To compare the clinical diagnosis and outcomes of preterm infants with bronchopulmonary dysplasia (BPD) under two different diagnostic criteria. Methods: A retrospective study was performed in 157 preterm infants who were admitted to Neonatal Intensive Care Unit of the Children's Hospital, Zhejiang University School of Medicine from January 2015 to December 2018. Enrolled infants, with gestational age <32 weeks and survived >14 days, met the 2001 National Institute of Child Health and Human Development(NICHD) definition of moderate and severe BPD or died between 14 days of postnatal age and 36 weeks owing to persistent parenchymal lung disease and respiratory failure. The severities of BPD were revaluated according to the 2018 revised definition of BPD proposed by NICHD. Characteristics and outcomes of these infants were compared with the two different diagnostic criteria with t-test, nonparametric test or Chi-square test. Results: In the 157 enrolled infants (100 males), severities of BPD were classified as moderate in 62, severe in 84 and unclassifiable in 11 according to the 2001 NICHD criteria, while grade Ⅰ in 51, Ⅱ in 29, Ⅲ in 66 and ⅢA in 11 infants respectively according to the 2018 NICHD criteria. Duration of oxygen therapy, positive pressure ventilation and endotracheal intubation in grade Ⅱinfants of 2018 criteria were much longer than that in moderate infants of 2001 criteria (80 (65, 95) vs. 65 (59, 77) d, 52 (38, 58) vs.30 (19, 48) d, 10 (2, 17) vs.4 (0, 12) d, Z=-2.995, -3.750, -2.073, all P<0.05). Mortality of moderate and severe infants in 2001 criteria was 10.3% (15/146), while mortality of BPD in 2018 criteria was 16.6% (26/157). Mortality of grade Ⅲ and ⅢA BPD in 2018 criteria was much higher than mortality of severe BPD in 2001 criteria (33.8% (26/77) vs. 17.9%(15/84), χ(2)=5.357, P<0.05). Conclusion: Definition and classification of BPD based on 2001 NICHD criteria may cause missed or unclassified cases, resulting in the underestimation of the morbidity and mortality of infants with severe BPD.