Comprehensive Data Extraction for Preterm Infants

A standard data abstraction form will be created using Microsoft Excel 2019 (Microsoft, Redmond, WA, USA, www.microsoft.com). Then, two independent reviewers will extract the basic characteristics and the data of outcomes. The extracted data will include the following: authors, gender, age, birthweight, year of publication, study design, inclusion criteria, medicine dosing protocol, sample size, primary closure rate, reopening rate, mortality, intraventricular hemorrhage (IVH all grades), necrotizing enterocolitis (NEC all grades), pulmonary hemorrhage (blood-stained liquid flowing from the trachea of the infant), bronchopulmonary dysplasia, retinopathy of prematurity, renal dysfunction, hepatic dysfunction, gastrointestinal bleeding, treatment methods, device used, median follow-up, PDA diameter, etc. If there is a discrepancy between the two reviewers, a third researcher will be consulted. We will randomly select five to ten studies to check the completeness of the data abstraction form. The data abstraction form will be complemented by the pilot trial. We will contact the corresponding author to query information when the essential data are insufficient or missing in the original study through sending an email. Studies will be excluded if we are unable to get access to the data, and the reasons for exclusion will be reported in detail.