Trends in the incidence and associated factors of late-onset sepsis associated with improved survival in extremely preterm infants born at 23-26 weeks' gestation: A retrospective study

Background: To investigate the trends in the incidence and associated factors of late-onset sepsis (LOS) associated with improved survival in extremely preterm infants. Methods: Medical records of 364 infants who were born at 23-26 weeks' gestation from 2000 to 2005 (period I, n=124) and from 2006 to 2011 (period II, n=240) were retrospectively reviewed. The infants were stratified into subgroups of 23-24 and 25-26 weeks' gestation within each period, and survival, LOS rate, and clinical characteristics were analyzed. Multivariate logistic regression analyses were completed to identify the clinical factors associated with LOS. Results: The survival rate of 75.8% during period I significantly improved to 85.4% during period II, especially in infants at 23-24 weeks' gestation (55.1% vs. 78.1%, respectively). The LOS rate of 33.1% during period I significantly reduced to 15.8% during period II, especially in infants at 25-26 weeks' gestation (32.0% vs. 8.9%, respectively). The LOS rate per 1000 hospital days of 4.0 during period I significantly reduced to 1.8 during period II. Candida presence reduced from 21.3% during period I to 4.7% during period II. In multivariate analyses, during period I, prolonged intubation, especially in infants at 25-26 weeks' gestation, and necrotizing enterocolitis, especially in infants at 23-24 weeks' gestation, were significantly associated with LOS. Conclusions: Improved survival of infants at 23-24 weeks' gestation was associated with a simultaneous reduction of LOS incidence in infants at 25-26 weeks' gestation. Less-invasive assisted ventilation may be one of the details of improved perinatal and neonatal care that has contributed to lowering risk of infection or death among periviable infants.