Bronchodilator response in school-aged preterm-born children who had chronic lung disease in infancy

Introduction: Preterm-born school-aged children, especially those who had chronic lung disease of prematurity (CLD) in infancy, have lower spirometry compared to term-born controls but the response to bronchodilators is unclear.

Aims: We compared spirometry before and after a single dose of salbutamol in school-aged children born preterm with and without CLD and those born at term.

Methods: From 253 children with mean age 10.5 years in our on-going RHiNO (Respiratory Health Outcomes in Neonates) study, 189 children were born at ≤34 weeks’ gestation, 61 had CLD in infancy and 128 did not; and 64 were term-born. Spirometry was performed before and 15 minutes after salbutamol inhalation via spacer device. Spirometry data were normalised against GLI reference values.

Results: The CLD group had significantly lower spirometry than the preterm and term controls (predicted %FEV1 84.5%, 91.5% and 94.2% respectively). Following bronchodilator %FEV1 improved significantly in all groups with the largest increase observed in the CLD group (post bronchodilator %FEV1: 90.4%, 95.8% and 97.7% for the CLD, preterm and term controls respectively). The increases were greatest for the smaller airways (predicted %FEF25-75% CLD 67.5%, 84.1%, Preterm 80.1%, 91.5% Term: 87.4%, 98.3% respectively before and after bronchodilator). A greater proportion of the CLD group but not the preterm group responded with ≥10% increase in %FEV1 than the term group (CLD 21%, Preterm 13%, Term 8%).

Discussion: We confirm that preterm-born children with CLD have low spirometry in childhood. Whilst the CLD group had greater response to bronchodilator, clinical efficacy needs assessment in a formal randomised control trial.