In a recently released article in Pediatrics(10.1542/peds.2020-030007), Dr. Erik Jensen and colleagues provide the first benchmark epidemiological data for the 2019 National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) recently proposed criteria for grading bronchopulmonary dysplasia (BPD). These revised definitions reflect a severity-based approach to the diagnosis of BPD, in which the condition is categorized by mode of respiratory support at 36 weeks postmenstrual age (PMA), regardless of the use or level of oxygen therapy. This new approach appears to better differentiate between those premature infants who did and did not develop poor neurodevelopmental and respiratory outcomes in early childhood. However, until this study, anchoring epidemiologic data have not been available.
If you are not a neonatologist (or if you are!), this is the study for you. It gives a broad and recent “30,000 foot view” of premature infant morbidity and mortality, highly relevant to all of us who follow former premature infants in our offices. The Vermont Oxford Network (VON) database includes a remarkable 85% of all premature infants born in the United States: this retrospective cohort study includes 24,896 very preterm infants born at 22-29 weeks’ gestation in 2018 at hospitals participating in VON. With respect to BPD, infants were categorized by the highest level of respiratory support they received at 36 0/7 weeks PMA: No BPD meant no respiratory support, BPD grade 1 & 2 (which could not be separated due to the detail level in the database) included those being treated with nasal cannula (any flow rate) or non-invasive positive airway pressure, and BPD grade 3 included those treated with invasive mechanical ventilation. The bottom line was that of studied infants, 2574 (10.3%) died prior to 36 weeks PMA, 12,198 (49.0%) were classified as not having BPD, 9192 (36.9%) 164 developed grade 1 or 2 BPD, and 932 (3.7%) developed grade 3 BPD.
I was surprised that just half of infants did not have BPD, but this describes the reality of current neonatal intensive care and actually represents a remarkable achievement after decades of translating research into clinical care. BPD severity is (not surprisingly) associated with other preterm morbidities, but the authors guide us through a thoughtful discussion on this topic – is there a causal relationship here or not, and how can this information drive thinking on next steps to prevent BPD? The authors also discuss the few evidence-based treatments for BPD, and describe the frequency of their use, which is another fascinating part of the study. Let us know what you think about this remarkable study, and how it helps you care for the former premature infants in your practice!
