Multicentre online registration of bronchopulmonary dysplasia in very preterm infants in China: protocol for a prospective, open, observational cohort study.

Introduction: Bronchopulmonary dysplasia (BPD) in very preterm infants (VPIs) has adverse long-term outcomes and affects the quality of survival. There are no registry studies on BPD in VPIs in China. Our aim was to conduct a prospective, multicentre, open, longitudinal, observational cohort study to investigate the epidemiological characteristics, diagnosis, treatment, and short-term and long-term outcomes of BPD in a real-life setting in China and lay the grounds for establishing a nationwide registry with clinical data and biological specimens.

Methods: This study aims to recruit a minimum of 2000 VPIs and start research in January 2024 in Shenzhen, China. We will collect clinical data from the beginning of the life of VPIs and follow them up to 3 years old. Short-term outcomes, such as the incidence of BPD, necrotising enterocolitis, retinopathy of prematurity, intraventricular haemorrhage and porencephalic ventricular leukomalacia, as well as the cost of hospitalisation, are the major variables of concern. Bayley-III Scale assessment, gross motor function and pulmonary function evaluation will be performed at the age of correction, that is, 18-24 months and 30-36 months. The follow-up outcomes include loss to follow-up, survival status, moderate-to-severe neurodevelopmental deficits and severe respiratory complications. Cord blood, peripheral blood, tracheal aspirate, faeces and urine from VPIs, as well as mother's milk, will be collected and stored at -80°C. All the data will be registered, stored and managed in a cloud-based database. This knowledge will be useful for establishing diagnostic criteria and predictive models for BPD in the Chinese population.

Ethics And Dissemination: Our protocol has been approved by the Medical Ethics Committee of Shenzhen People's Hospital (LL-KY-2023174-02) and the local ethics committee of each participating centre. Our goal is to present our findings at national conferences and in peer-reviewed paediatric journals.

Trial Registration Number: Chinese Clinical Trial Registry (ChiCTR2400081615).