Neonatal Outcomes of Very Low Birth Weight Infants in Korean Neonatal Network from 2013 to 2016

Abstract

Background: This study was performed to determine survival and morbidity rates in very low birth weight infants (VLBWIs) in the Korean Neonatal Network (KNN), and to compare neonatal outcomes with those in other countries.

Methods: Data were collected for 8,269 VLBWIs with gestational age (GA) ≥ 22 weeks who were born between January 1, 2013 and December 31, 2016, and admitted to the neonatal intensive care units of the KNN.

Results: The survival rate of all VLBWIs and of infants with GA 22-23, 24-25, 26-27, 28-29, 30-32, and > 32 weeks were 86% (total), 33%, 65%, 84%, 94%, 97%, and 98%, respectively. The bronchopulmonary dysplasia (BPD) rates of all VLBWIs and of infants with GA 22-23, 24-25, 26-27, 28-29, 30-32, and > 32 weeks were 30% (total), 88%, 64%, 47%, 26%, 14%, and 5%, respectively. The intraventricular hemorrhage rates (≥ grade III) of all VLBWIs and of infants with GA 22-23, 24-25, 26-27, 28-29, 30-32, and > 32 weeks were 10% (total), 45%, 27%, 12%, 5%, 2%, and 1%, respectively. In an international comparison, the survival rate of VLBWIs with GA 24-27 weeks in KNN was lower, and the BPD rate of VLBWIs in the KNN was higher than that of the neonatal networks of other countries.

Conclusion: Despite overall improvements in neonatal outcomes, the survival and morbidity rates of more immature infants with GA 22-27 weeks need further improvement. Therefore, it would be necessary to develop more optimal treatment strategies and perform more active quality improvement to further improve neonatal outcomes of VLBWIs in Korea.

Keywords: Bronchopulmonary Dysplasia; Infant Mortality; Infant, Premature; Infant, Very Low Birth Weight.

Fig. 1. Annual trends of neonatal outcomes of VLBWIs of KNN (2013–2016).

VLBWIs = very low birth weight infants, KNN = Korean Neonatal Network, BPD = bronchopulmonary dysplasia, moderate to severe, IVH (≥ grade III) = grade III or more intraventricular hemorrhage, PVL = periventricular leukomalacia, cystic, ROP Tx. = therapy for retinopathy of prematurity. ^*P value < 0.05 evaluated with χ² Fisher's exact test, compared with outcomes in 2013.

Fig. 2. International comparison of moderate to severe BPD, severe ROP (≥ stage III), NEC (≥ stage II_a), sepsis, and IVH (≥ grade III) or cystic PVL in VLBWIs with 22–32 weeks' gestation.

BPD = bronchopulmonary dysplasia, ROP = retinopathy of prematurity, NEC = necrotizing enterocolitis, IVH = intraventricular hemorrhage, PVL = periventricular leukomalacia, VLBWIs = very low birth weight infants, KNN = Korean Neonatal Network, CNN = Canandian Neonatal Network, NRNJ = Neonatal Research Network of Japan. ^*P value < 0.05 evaluated with χ² Fisher's exact test, compared with outcomes of the KNN; ^†sepsis at ≥ 3 days of life; ^‡sepsis at ≥ 7 days of life; ^a2013–2016; ^b2006–2008.