National registry data from Korean neonatal network: Two-year outcomes of Korean very low birth weight infants born in 2013-2014

Background: The aim of this study was to observe long-term outcomes of very low birth weight infants (VLBWIs) born between 2013 and 2014 in Korea, especially focusing on neurodevelopmental outcomes. Methods: The data were collected from Korean Neonatal Network (KNN) registry from 43 and 54 participating units in 2013 and 2014, respectively. A standardized electronic case report form containing 30 items related to long-term follow up was used after data validation. Results: Of 2,660 VLBWI, the mean gestational age and birth weight were 29 ^1/7 ± 2 ^6/7 weeks and 1,093 ± 268 g in 2013 and 29 ^2/7 ± 2 ^6/7 weeks and 1,125 ± 261 g in 2014, respectively. The post-discharge mortality rate was 1.2%-1.5%. Weight < 50th percentile was 46.5% in 2013 and 66.1% in 2014. The overall prevalence of cerebral palsy among the follow up infants was 6.2% in 2013 and 6.6% in 2014. The Bayley Scales of Infant Developmental Outcomes version II showed 14%-25% of infants had developmental delay and 3%-8% of infants in Bayley version III. For the Korean developmental screening test for infants and children, the area "Further evaluation needed" was 5%-12%. Blindness in both eyes was reported to be 0.2%-0.3%. For hearing impairment, 0.8%-1.9% showed bilateral hearing loss. Almost 50% were readmitted to hospital with respiratory illness as a leading cause. Conclusion: The overall prevalence of long-term outcomes was not largely different among the VLBWI born between 2013 and 2014. This study is the first large national data study of long-term outcomes.