Follow up study of infants recruited to the randomised, placebo-controlled trial of azithromycin for the prevention of chronic lung disease of prematurity in preterm infants – Study protocol for the AZTEC-FU Study

Background: Preterm birth, especially at less than 30 weeks’ gestation, is significantly associated with respiratory, neurodevelopmental and growth abnormalities. The AZTEC study has recruited 799 infants born at <30 weeks’ gestation to determine if a ten-day intravenous treatment with azithromycin improves survival without development of chronic lung disease of prematurity (CLD) at 36 weeks’ post menstrual age (PMA) when compared to placebo. The follow up studies will compare respiratory, neurodevelopmental and growth outcomes up to 2 years of corrected age between infants who received azithromycin and those who received placebo in the early neonatal period. Methods: : Survivors at 36 weeks’ PMA from the main AZTEC study with parental consent will continue to be followed up to discharge from the neonatal unit and to two years of corrected age. Length of stay, rates of home oxygen, length of supplemental oxygen requirement, hospital admissions, drug usage, respiratory illness, neurodevelopmental disability and death rates will be reported. Data is being collected via parentally completed respiratory and neurodevelopmental questionnaires at one and two years of corrected age respectively and additional information is being obtained from various sources including hospital discharge and clinical letters from general practitioners and hospitals as well as from national databases including the National Database Analyses Unit and NHS Digital. Discussion: The AZTEC-FU will assess mortality and important neonatal morbidities including respiratory, neurodevelopmental and growth outcomes. Important safety data will also be collected, including the incidence of potential consequences of early macrolide use, primarily pyloric stenosis. This study may have implications on future neonatal care. Trial registration: The study was retrospectively registered on ISRCTN (ISRCTN47442783).