Pulmonary Function and Bronchopulmonary Dysplasia Classification: Insights from the Spanish Registry

Abstract

In 2016, the Spanish Research Group on Bronchopulmonary Dysplasia (BPD) (GEIDIS) established a national registry with participation of 66 hospitals to collect information on clinical characteristics and long-term outcomes of BPD infants into adulthood. The aim of this study is to examine forced spirometry data in early childhood and to assess their correlation with the respiratory support required at 36 weeks postmenstrual age (PMA). The study analyzed data from preterm infants with BPD born between January 2016 and December 2017 who underwent forced spirometry at 5-7 years of age. Statistical analyses were conducted to investigate the relationships between spirometry results, perinatal factors, and the required respiratory support at 36 weeks PMA. The study involved 143 patients with a median gestational age (GA) of 27.3 weeks (range: 25.7-28.7) and a median weight of 880 grams (range: 740-1135). Pathological spirometry was observed in 39.2% (56) of the patients. Among patients diagnosed with BPD type 3, those requiring over 30% oxygen at 36 weeks PMA exhibited an increased risk of pathological spirometry (OR 4.48; 95% CI: 1.11-18.13) compared to those requiring positive pressure with less than 30% oxygen. In addition, this subgroup had a higher risk of developing a restrictive-mixed pattern compared to those with BPD type 1 (OR 10,65; 95% IC 2,06-54,98) and BPD type 2 (OR 6,76; 95% IC 1,09-42,06). No significant differences were found in the incidence of an obstructive pattern between BPD types. Additionally, the study revealed distinct etiopathogenic mechanisms underlying the development of restrictive versus obstructive patterns. The requirement of more than 30% oxygen at 36 weeks PMA serves as a risk indicator for pulmonary function impairment in school-aged children with BPD. These findings suggest persistent airway and parenchymal injury in this specific patient population, and highlight the importance of careful monitoring to evaluate their long-term effects on lung function.