Increasing airway obstruction through life following bronchopulmonary dysplasia: a meta-analysis

Abstract

Background Few studies exist investigating lung function trajectories of those born preterm; however growing evidence suggests some individuals experience increasing airway obstruction throughout life. Here we use the studies identified in a recent systematic review to provide the first meta-analysis investigating the impact of preterm birth on airway obstruction measured by the forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) ratio. Methods Cohorts were included for analysis if they reported FEV1/FVC in survivors of preterm birth (<37 weeks’ gestation) and control populations born at term. Meta-analysis was performed using a random effect model, expressed as standardised mean difference (SMD). Meta-regression was conducted using age and birth year as moderators. Results 55 cohorts were eligible, 35 of which defined groups with bronchopulmonary dysplasia (BPD). Compared to control populations born at term, lower values of FEV1/FVC were seen in all individuals born preterm (SMD −0.56), with greater differences seen in those with BPD (SMD −0.87) than those without BPD (SMD −0.45). Meta-regression identified age as a significant predictor of FEV1/FVC in those with BPD with the FEV1/FVC ratio moving −0.04 sds away from the term control population for every year of increased age. Conclusions Survivors of preterm birth have significantly increased airway obstruction compared to those born at term with larger differences in those with BPD. Increased age is associated with a decline in FEV1/FVC values suggesting increased airway obstruction over the life course.