Changes in Survival Rate for Very-Low-Birth-Weight Infants in Korea: Comparison with Other Countries

Abstract

Recently the Korean Neonatal Network (KNN) was established in order to enhance treatment outcomes further through the registration of very-low-birth-weight infants (VLBWI) data. The present study was conducted on 2,606 VLBWI, 2,386 registered and 220 un-registered, in the KNN participating centers, with the objective of reporting on recent survival rates of VLBWI in Korea and verifying the changing trends in survival rates with data from the 1960s and beyond. The study also aimed to compare the premature infants' survival rate in Korea with those reported in neonatal networks of other countries. The recent survival rate of VLBWI increased more than twice from 35.6% in the 1960s to 84.8%, and the survival rate of the extremely low birth weight infants (ELBWI) increased by more than 10 times, indicating improvement of the survival rate in premature infants with lower birth weight and gestational age. Comparison of VLBWI between countries showed improved survival rates according to each birth weight group in Canada, Australia-New Zealand, and European countries with Japan at the head, but in terms of comparison based on gestational age, differences, except for Japan, have been reduced. Efforts to increase the survival rate of premature infants in Korea with low birth rate are inevitable, and they should be the foundation of academic and clinical development based on its network with advanced countries.

Keywords: Gestational Age; Infant, Extremely Low Birth Weight; Infant, Newborn; Intensive Care, Neonatal; Mortality; Survival Rate.

Fig. 1. Flow chart depicting the process of study. ^*Data acquisition from Kim et al., Korean J Pediatr 2008 (reference 17); ^†data acquisition from Park et al., J Korean Soc Neonatol 2004 (reference 5); ^‡data acquisition from Hahn et al., J Korean Soc Neonatol 2009 (reference 6); ^§data acquisition from Hahn et al., J Korean Med Sci 2011 (reference 7).

Fig. 2. Changes of neonatal survival rates for very-low-birth-weight infants (VLBWI) and extremely low birth weight infants (ELBWI) in Korea (1960-2014. 6.). ^*P < 0.05 vs. late 1960s; ^†P < 0.001 vs. late 1960s; ^‡P < 0.05 vs. late 1960s; ^§P < 0.001 vs. late 1960s; ^∥data acquisition from Kim et al., Korean J Pediatr 2008 (reference 17); Park et al., J Korean Soc Neonatol 2004 (reference 5); Hahn et al., J Korean Soc Neonatol 2009 (reference 6) and Hahn et al., J Korean Med Sci 2011 (reference 7). ELBWI, extremely low birth weight infants; VLBWI, very-low-birth-weight infants.

Fig. 3. Changes of neonatal survival rates by gestational period in Korea (2002-2014. 6). ^*P < 0.015, 2007 vs. 2002; ^†P < 0.015, 2009 vs. 2002; ^‡P < 0.015, 2013-2016.6 vs. 2002; ^§data acquisition from Park et al., J Korean Soc Neonatol 2004 (reference 5); ^∥data acquisition from Hahn et al., J Korean Soc Neonatol 2009 (reference 6); ^¶data acquisition from Hahn et al., J Korean Med Sci 2011 (reference 7).

Fig. 4. Comparison of neonatal survival rate in Korea, Japan, Europe, Canada, and Autralia-New Zealand by very-low-birth-weight infants (VLBWI) and extremely low birth weight infants (ELBWI). ^*P < 0.05 comparison to the KNN reference birth weight specific survival rates. KNN, Korean Neonatal Network; NRNJ, Neonatal Research Network of Japan (reference 20); NICHD, National Institute of Child Health and Human Development Neonatal Research Network (U.S., reference 11); CNN, Canadian Neonatal Network (reference 21); AZN, Australia-New Zealand Neonatal Network (reference 22); EuroNeoNet, European Neonatal Network (reference 23); ELBWI, extremely low birth weight infants; VLWBI, very-low-birth-weight infants.