Long-term respiratory outcomes in school-aged children born before 32 weeks of gestation

Preterm infants with bronchopulmonary dysplasia (BPD) are at increased risk of respiratory morbidity in the early years of life, including higher rates of persistent wheezing, asthma, and hospital admissions. The objective was to assess respiratory symptoms at school age in a cohort of very and extremely preterm infants with and without BPD. We conducted a prospective observational study of infants born before 32 weeks of gestation who were admitted to our neonatal unit between January 2012 and December 2014. Diagnosis and grade of BPD were defined according to the NIH consensus. Follow-up was performed after hospital discharge, and respiratory symptoms were assessed between 7 and 10 years of age using the Global Asthma Network (GAN) questionnaire. Of the 327 patients born during the study period, 94 completed the GAN questionnaire (mean age 8.6 years, SD 0.8). Overall, 51% reported wheezing, which was more common in the BPD 2-3 group (75%) than in the no BPD/1 group (47%) (p = 0.03), a difference that remained significant after adjustment for gestational age (OR 3.15, 95% CI 1.01 - 10.01). Asthma symptoms were also more common in the BPD 2-3 group (40%) compared to the no BPD/1 group (12%) (p < 0.01). Respiratory hospitalizations in the first 2 years of life were significantly higher in the BPD 2-3 group (61% vs. 25%, p = 0.01), with a fourfold increased risk after adjustment for gestational age (OR 4.7, 95% CI 1.5 - 14.6). No significant differences in wheezing were found between patients without BPD and those with grade 1 BPD (55% vs. 22%, p = 0.07), or between those born before and after 28 weeks' gestation (59% vs. 51%, p = 0.52).

In our population of preterm school-aged children, those with grade 2 or 3 BPD had significantly higher rates of wheezing, asthma symptoms, and hospital admissions in the first two years of life than those without BPD or with grade 1 BPD. There were no significant differences in respiratory symptoms between patients with no BPD and those with grade 1 BPD, nor between those born before or after 28 weeks' gestation.

• Preterm infants with BPD are at higher risk of developing respiratory problems such as wheezing and asthma during childhood. Most existing data come from older cohorts, and recent improvements in neonatal care may have modified long-term respiratory outcomes.

• In this recent cohort of very and extremely preterm infants, those with grade 2 or 3 BPD showed significantly higher rates of wheezing, asthma symptoms, and early hospitalizations. No differences were observed between children with no BPD and those with grade 1 BPD, nor between those born before or after 28 weeks' gestation. These findings highlight the impact of BPD severity on long-term respiratory morbidity.