Bronchopulmonary Dysplasia, Then and Now: Comparison of Outcomes and Evolving Determinants of Disease

Background: Bronchopulmonary dysplasia (BPD) is the most common and severe chronic lung disease seen in premature infants, yet its multifactorial etiology and complex pathophysiology remain unclear. Despite the prevalence, and the considerable morbidity and mortality associated with the disease, there has not been a universally accepted definition of BPD. Currently, the most commonly accepted definition of BPD is the need for oxygen supplementation at 36 weeks corrected gestational age (GA). This study compares the clinical characteristics of neonates diagnosed with BPD, and specific respiratory outcomes in early 2000’s and 10 years later our NICU.

Methods: Infants born < 30 weeks of gestation and at ≤ 1000 grams, were admitted to the NICU between the years of 2006-2008 (Cohort A) and 2016-2018 (Cohort B), received supplemental oxygen, and who were diagnosed with BPD were included in the study. Subjects with major congenital renal or heart anomalies were excluded. Infants born between these two time periods were compared on a number of factors, including maternal, prenatal, neonatal clinical course, and socioeconomic determinants.

Results: Infants in Cohort A had higher GA (27.8 weeks vs 25.6 weeks) and greater birthweight (BW) (1064 grams vs 797 grams), p<0.001 and p<0.001, respectively. Furthermore, Cohort B had lower APGAR scores at both 1- and 5-minutes (p < 0.01, both) and shorter NICU stays (56.7 vs 73.9 days, p<0.01) than their Cohort A peers. There was no difference in neonatal race or gender, maternal demographics, or substance use history between the two cohorts. There were more mothers with hypertension, p>0.0001 in Cohort B. Antenatal steroids and surfactant were administered less in Cohort B (p < 0.05 and p<0.01, respectively), while there was no difference in the amount of postnatal steroids used. There was no difference in the duration of ventilation or Vapotherm provided, however, patients in Cohort B received fewer days of respiratory therapy overall (p < 0.001), fewer days of CPAP (p=0.0003), and fewer days on oxygen (p < 0.008).

Conclusion: Despite being born nearly two weeks earlier and over two-hundred grams smaller than their Cohort A peers, the newborns of Cohort B spent significantly shorter lengths of time in the NICU and received significantly less respiratory and oxygen support.