Supplementary Material for: Late-onset sepsis among extremely preterm infants of 24-28 weeks gestation – An international comparison in 10 high-income countries

Introduction: Despite advances in neonatal care, late-onset sepsis remains an important cause of preventable morbidity and mortality. Neonatal late-onset sepsis rates have decreased in some countries, while in others they have not. Our objective was to compare trends in late-onset sepsis rates in 9 population-based networks from 10 countries and to assess the associated mortality within 7 days of late-onset sepsis.
Methods: We performed a retrospective population-based cohort study. Infants born at 24-28 weeks’ gestation between 2007-2019 were eligible for inclusion. Late-onset sepsis was defined as a positive blood or cerebrospinal fluid culture. Late-onset sepsis rates were calculated for 3 epochs (2007-11, 2012-15, 2016-19). Adjusted risk ratio’s (aRR’s) for late-onset sepsis were calculated for each network.
Results: Of a total of 82,850 infants, 16,914 (20.4%) had late-onset sepsis, with Japan having the lowest rate (7.1%) and Spain the highest (44.6%). Late-onset sepsis rates decreased in most networks and remained unchanged in a few. Israel, Sweden and Finland showed the largest decrease in late-onset sepsis rates. The aRR’s for late-onset sepsis showed wide variations between networks. The rate of mortality temporally-related to late-onset sepsis was 10.9%. The adjusted mean length of stay for infants with late-onset sepsis was increased by 5-18 days compared to infants with no late-onset sepsis.
Conclusions: One in 5 neonates of 24-28 weeks’ gestation develops late-onset sepsis. Wide variability in late-onset sepsis rates exists between networks with most networks exhibiting improvement. Late-onset sepsis was associated with increased mortality and length of stay.