Longitudinal impairment of lung function in school-age children with extremely low birth weights

OBJECTIVES To assess lung function and long-term respiratory outcomes in extremely low birth weight (ELBW) survivors. WORKING HYPOTHESIS ELBW, especially with respiratory complications in the neonatal period, affects lung function at a later age. STUDY DESIGN Longitudinal retrospective study. PATIENT-SUBJECT SELECTION Lung function was evaluated in 89 ELBW survivors (at ages 8 and 12) with or without a history of bronchopulmonary dysplasia (BPD) or a bubbly/cystic lung appearance in the neonatal period. METHODOLOGY FVC, FEV1, FEF50, and FEF75 were measured using spirometry. Two-way repeated-measures ANOVA was used to compare lung function and deterioration time course from 8 to 12 years of age. RESULTS Lung function variables were significantly and positively correlated between 8 and 12 years: %FVC (R2 = 0.558), %FEV1 (R2 = 0.539), %FEF50 (R2 = 0.412), and %FEF75 (R2 = 0.429). Lung function values were lower than Japanese reference values, especially in children with a history of severe BPD or a bubbly/cystic appearance. %FEV1 and FEV1/FVC ratio worsened from 8 to 12 years of age: 83.0 ± 17.0% versus 76.6 ± 17.8% (mean difference, 95%CI: −6.43, −9.10 to −3.75) and 84.0 ± 10.1% versus 78.2 ± 13.4% (mean difference, 95%CI: −5.82, −8.56 to −3.08), regardless of whether or not there was a history of neonatal respiratory disease. CONCLUSIONS In ELBW survivors, the obstructive pattern of lung function impairment deteriorated from 8 to 12 years of age, independent of the presence of severe BPD or bubbly/cystic appearance in the neonatal period.