Trends in the neurodevelopmental outcomes among preterm infants from 2003-2012: a retrospective cohort study in Japan

Objectives To determine the trends in mortality and the prevalence of abnormal neurodevelopmental outcomes among preterm Japanese infants. Study design A retrospective multicenter cohort of 30,793 preterm infants born at a gestational age 32 weeks, between 2003 and 2012, in the Neonatal Research Network, Japan, was evaluated in the primary analysis. Finally, 13,661 infants were followed-up until 3 years of age and evaluated for neurodevelopmental outcomes, including cerebral palsy (CP), home oxygen therapy (HOT) use, and visual, hearing, and cognitive impairments. Multivariable logistic regression analysis was performed to determine the risk-adjusted trends in mortality and long-term neurodevelopmental outcomes. Results The trends in overall mortality (adjusted odds ratio, (AOR): 0.92; 95% confidence interval, (CI): 0.89-0.94), the prevalence of CP (AOR: 0.95, 95% CI: 0.92-0.98), HOT use (AOR: 0.84, 95% CI: 0.75-0.93), and visual (AOR: 0.84, 95% CI: 0.81-0.87) and hearing impairments (AOR: 0.78, 95% CI: 0.63-0.97) showed a significant downward trend, while cognitive impairment showed no significant changes (AOR: 1.02, 95% CI: 0.99-1.05). Intravenous hyperalimentation was significantly correlated with visual impairment (AOR 0.74, 95% CI 0.59-0.91). Early establishment of enteral feeding was associated with improved long-term outcomes. Conclusions Mortality was improved, and this did not lead to increased risks for abnormal neurodevelopmental outcomes. Nutritional support might improve long-term neurodevelopmental outcomes.