Examining the severity of bronchopulmonary dysplasia in very preterm infants

Severity-based diagnostic criteria for bronchopulmonary dysplasia were recently proposed by the Human Development Neonatal Research Network and Eunice Kennedy Shriver National Institute of Child Health. A report in Pediatrics offers the first epidemiological data that applies these new criteria.¹

The investigators performed a retrospective cohort study of infants who were born from 22 to 29 weeks’ gestation in 2018 at 715 hospital in the United States that were part of the Vermont Oxford Network. They determined the major neonatal morbidities, rates of bronchopulmonary dysplasia, and common respiratory therapies and stratified them by bronchopulmonary dysplasia severity.

There were 24,986 infants included in the study. In this cohort, 2574 of them died before 36 weeks’ postmenstrual age; 12,198 of the infants did not develop bronchopulmonary dysplasia; 9192 developed grade 1 or 2 bronchopulmonary dysplasia; and 932 developed grade 3 bronchopulmonary dysplasia. The rates of mortality before 36 weeks' postmenstrual age and grade 3 bronchopulmonary dysplasia declined from 52.7% and 9.9%, respectively, among infants born at 22 weeks' gestation to 17.3% and 0.8% among infants born at 29 weeks' gestation. Bronchopulmonary dysplasia grade 1 or 2 had a peak in incidence among infants who were born at 25 weeks’ gestation. Frequency of cystic periventricular leukomalacia or severe intraventricular hemorrhage increased from 4.8% among survivors without bronchopulmonary dysplasia to 23.4% among survivors who had grade 3 bronchopulmonary dysplasia. The investigators observed similar ranges with surgically treated necrotizing enterocolitis (1.4%–17.1%), severe retinopathy of prematurity (1.2%–23.0%), late onset sepsis (4.8%–31.4%), and home oxygen therapy (2.0%–67.5%).

The investigators concluded that over half of very preterm infants who were born in the United States either died before 36 weeks’ postmenstrual age or developed bronchopulmonary dysplasia. Additionally, greater severity of bronchopulmonary dysplasia was linked to more frequent development of major neonatal morbidities, use of supplemental respiratory support at the time of discharge, and in-hospital mortality.

Reference

1. Jansen E, Edwards E, Greenberg L, Soll R, Ehret D, Horbar J. Severity of bronchopulmonary dysplasia among very preterm infants in the United States. Pediatrics. June 2, 2021. Epub ahead of print. doi:10.1542/peds.2020-030007