Abstract
Advances in neonatal intensive care have significantly reduced mortality and morbidity in extremely preterm infants (EPIs). However, the incidence of bronchopulmonary dysplasia (BPD) remains similar or is even increasing. This study examines trends in mortality, BPD, and composite outcome of BPD or mortality among EPIs in Korea. We analyzed data from the Korean Neonatal Network, a nationwide cohort of preterm infants in Korea. EPIs with gestational ages of 23-27 weeks born between 2014 and 2021 were included. Among 4,450 survivors (mean gestational age 25.7 ± 1.2 weeks, mean birth weight 870.7 ± 194.2 g), the incidence of BPD rose from 51.2 to 62.7% (P < 0.001), while mortality declined from 28.3 to 19.5% (P < 0.001). The composite outcome of BPD or mortality also increased, from 63.6 to 66.9% (P = 0.006). The duration of invasive ventilation, rates of endotracheal intubation at birth, and intubation for surfactant administration decreased, whereas the duration of non-invasive ventilation and overall ventilatory support increased. Despite decreasing mortality, the incidence of BPD among survivors and composite outcome of BPD or mortality increased, potentially driven by longer ventilatory support. This suggests a trade-off where improved survival rates in EPIs lead to a higher incidence of BPD.