Bubbly and cystic appearance on chest radiograph of extremely preterm infants with bronchopulmonary dysplasia is associated with wheezing disorder

Aim Bubbly/cystic appearance on chest X-ray (CXR) is an important factor in cases of severe bronchopulmonary dysplasia (BPD). We aimed to determine whether CXR -based BPD classifications obtained in extremely preterm infants with oxygen dependency at 28 days after birth (BPD28) is associated with wheezing disorders. Methods This was a multicentre retrospective cohort study of population data from infants (body weight, <1500 g) enrolled in the Neonatal Research Network of Japan. Of the 15 480 infants born at <28 weeks of gestation between 2003 and 2012, 8979 met the BPD28 criteria, and 4007 were classified as the no BPD28 group. BPD28 infants were classified according to the bubbly/cystic or no bubbly/cystic appearance on CXR at postnatal >= 28 days. The effects on wheezing disorder at 3 years of age were analysed. Results Bubbly/cystic BPD28 infants showed higher rates of wheezing disorders compared with no BPD28 infants. Bubbly/cystic BPD28 (odds ratio 1.7; 95% confidence interval, 1.3-2.2) was a significant independent factor for wheezing disorders. Conclusion A bubbly/cystic appearance on CXR with BPD28 was a potential risk factor of wheezing disorders at 3 years of age. This may be a useful early diagnostic tool at >= 28 postnatal days in extremely preterm infants.