Pulmonary function and bronchopulmonary dysplasia classification: insights from the Spanish Registry

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 observational 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 g (range 740–1135). Abnormal spirometry results were 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 abnormal spirometry results (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% CI 2.06–54.98) and BPD type 2 (OR 6.76; 95% CI 1.09–42.06). No significant differences were found in the incidence of an obstructive pattern between BPD types.