Long-term outcomes of preterm infants in the first 6 years of life: a nationwide population-based study in Korea

This study examined the relationship between gestational age and long-term outcomes up to 6 years of age using population-based big data from the National Health Insurance Service in Korea. This retrospective observational cohort study used data from the National Health Information Database (2011-2017). All children born in Korea during 2011 (January 1-December 31) were eligible and were followed up until 2017. Gestational age groups were divided into extremely preterm (< 28 weeks), very preterm (28-31 weeks), moderate-to-late preterm (32-36 weeks), and full-term (37-41 weeks). The survival rate, neurodevelopmental diseases, hearing or visual impairment, and respiratory morbidities were compared for each gestational age group. In total, 370,301 children were included in the analysis. The total survival rate increased with increasing gestational age. Furthermore, the risk of neurodevelopmental diseases (i.e., epilepsy, cerebral palsy, delayed development, mental retardation, language disorder, developmental coordination disorder, autism spectrum disorder), hearing or visual impairment, and asthma-related inhaler prescription increased with decreasing gestational age, despite adjustment for covariates. Conclusion: Lower gestational age was associated with an increase in a wide spectrum of adverse neurodevelopmental and respiratory outcomes in the first 6 years of life. Although morbidities were highest at the earliest gestational ages, moderate-to-late preterm children were significantly associated with increased adverse outcomes compared with full-term children. Our findings prove this under-recognized group's long-term follow-up and policy support. What is Known: center dot Infants born preterm are at high risk for neurodevelopmental and various medical health problems. center dot Nationwide research on long-term outcomes for moderate-to-late preterm birth is sparse. What is New: center dot In this nationwide cohort study, lower gestational age at birth was inversely associated with increased adverse neurodevelopmental and respiratory outcomes in the first 6 years of life. center dot Long-term follow-up and policy support are required for moderate-to-late preterm children who are at risk of increased adverse outcomes compared with full-term births.