J Korean Med Sci.  2015 Oct;30(Suppl 1):S25-S34. 10.3346/jkms.2015.30.S1.S25.

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

• Shim JW
• Jin HS
• Bae CW

• KMID: 2351133
• DOI: http://doi.org/10.3346/jkms.2015.30.S1.S25

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.

Keyword

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

MeSH Terms

Databases, Factual
Europe
Gestational Age
Humans
Infant
Infant Mortality/*trends
Infant, Extremely Low Birth Weight
Infant, Newborn
Infant, Premature
*Infant, Very Low Birth Weight
Japan
Republic of Korea

Figure

• 

  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.

Reference

1. Patel RM, Kandefer S, Walsh MC, Bell EF, Carlo WA, Laptook AR, Sánchez PJ, Shankaran S, Van Meurs KP, Ball MB, et al. Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Causes and timing of death in extremely premature infants from 2000 through 2011. N Engl J Med. 2015; 372:331–340.

2. Ancel PY, Goffinet F, Kuhn P, Langer B, Matis J, Hernandorena X, Chabanier P, Joly-Pedespan L, Lecomte B, Vendittelli F, et al. EPIPAGE-2 Writing Group. EPIPAGE-2 Writing Group. Survival and morbidity of preterm children born at 22 through 34 weeks' gestation in France in 2011: results of the EPIPAGE-2 cohort study. JAMA Pediatr. 2015; 169:230–238.

3. Stoll BJ, Hansen NI, Bell EF, Shankaran S, Laptook AR, Walsh MC, Hale EC, Newman NS, Schibler K, Carlo WA, et al. Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Neonatal outcomes of extremely preterm infants from the NICHD Neonatal Research Network. Pediatrics. 2010; 126:443–456.

4. Agarwal P, Sriram B, Rajadurai VS. Neonatal outcome of extremely preterm Asian infants ≤28 weeks over a decade in the new millennium. J Perinatol. 2015; 35:297–303.

5. Park DK, Kil CH, Bae CW. Neonatal statistics of Korea in 2002: collective results of live-births, and neonatal mortality rates from 62 hospitals. J Korean Soc Neonatol. 2004; 11:122–129.

6. Hahn WH, Chang JY, Bae CW. Birth statistics and mortality rates for neonatal intensive care units in Korea during 2007: collective results from 57 hospitals. J Korean Soc Neonatol. 2009; 16:36–47.

7. Hahn WH, Chang JY, Chang YS, Shim KS, Bae CW. Recent trends in neonatal mortality in very low birth weight Korean infants: in comparison with Japan and the USA. J Korean Med Sci. 2011; 26:467–473.

8. Korean Statistical Information Service. Birth statistics. accessed on 20 April 2015. Available at http://www.kosis.kr/.

9. Moon JY, Hahn WH, Shim KS, Chang JY, Bae CW. Changes of maternal age distribution in live births and incidence of low birth weight infants in advanced maternal age group in Korea. Korean J Perinatol. 2011; 22:30–36.

10. Choi SH, Park YS, Shim KS, Choi YS, Chang JY, Hahn WH, Bae CW. Recent trends in the incidence of multiple births and its consequences on perinatal problems in Korea. J Korean Med Sci. 2010; 25:1191–1196.

11. Horbar JD, Carpenter JH, Badger GJ, Kenny MJ, Soll RF, Morrow KA, Buzas JS. Mortality and neonatal morbidity among infants 501 to 1500 grams from 2000 to 2009. Pediatrics. 2012; 129:1019–1026.

12. Kim TH, Choi MS, Chung SH, Choi YS, Bae CW. Morbidity of low birth weight infants in Korea (2012): a comparison with Japan and the USA. Neonatal Med. 2014; 21:218–223.

13. Shah PS, Lee SK, Lui K, Sjörs G, Mori R, Reichman B, Håkansson S, Feliciano LS, Modi N, Adams M, et al. International Network for Evaluating Outcomes of Neonates (iNeo). The international network for evaluating outcomes of very low birth weight, very preterm neonates (iNeo): a protocol for collaborative comparisons of international health services for quality improvement in neonatal care. BMC Pediatr. 2014; 14:110.

14. Kramer MS, Platt RW, Yang H, Haglund B, Cnattingius S, Bergsjo P. Registration artifacts in international comparisons of infant mortality. Paediatr Perinat Epidemiol. 2002; 16:16–22.

15. Isayama T, Lee SK, Mori R, Kusuda S, Fujimura M, Ye XY, Shah PS. Canadian Neonatal Network. Neonatal Research Network of Japan. Canadian Neonatal Network; Neonatal Research Network of Japan. Comparison of mortality and morbidity of very low birth weight infants between Canada and Japan. Pediatrics. 2012; 130:e957–e965.

16. Chang YS, Ahn SY, Park WS. The establishment of the Korean Neonatal Network (KNN). Neonatal Med. 2013; 20:169–178.

17. Kim KS, Bae CW. Trends in survival rate for very low birth weight infants and extremely low birth weight infants in Korea, 1967-2007. Korean J Pediatr. 2008; 51:237–242.

18. Kim DH, Shim SY, Kim JR, Shin SH, Kim ES, Joung KE, Kim SD, Lee JA, Choi CW, Kim EK, et al. Recent outcome of extremely low birth weight infants: the use of CRIB(clinical risk index for babies) II score for analyzing the survival rate. Korean J Pediatr. 2006; 49:952–958.

19. Egger M, Smith GD. Meta-analysis. Potentials and promise. BMJ. 1997; 315:1371–1374.

20. Neonatal Research Network Japan. accessed on 20 April 2015. Available at http://nrn.shiga-med.ac.jp/Englishdefault.htm.

21. The Canadian Neonatal Network TM. accessed on 20 April 2015. Available at http://www.canadianneonatalnetwork.org/portal/.

22. Australian & New Zealand Neonatal Network (ANZNN). National Perinatal Epidemiology and Statistics Unit (NPESU). accessed on 20 April 2015. Available at https://npesu.unsw.edu.au/data-collection/australian-new-zealand-neonatal-network-anznn.

23. European Neonatal Network. EuroNeoNet. accessed on 20 April 2015. Available at http://www.euroneonet.eu/paginas/publicas/euroneo/euroNeoNet/index.html.

24. Hanley JA, Negassa A, Edwardes MD, Forrester JE. Statistical analysis of correlated data using generalized estimating equations: an orientation. Am J Epidemiol. 2003; 157:364–375.

25. Hubbard AE, Ahern J, Fleischer NL, Van der Laan M, Lippman SA, Jewell N, Bruckner T, Satariano WA. To GEE or not to GEE: comparing population average and mixed models for estimating the associations between neighborhood risk factors and health. Epidemiology. 2010; 21:467–474.

26. Shah PS, Sankaran K, Aziz K, Allen AC, Seshia M, Ohlsson A, Lee SK. Canadian Neonatal Network. Outcomes of preterm infants <29 weeks gestation over 10-year period in Canada: a cause for concern? J Perinatol. 2012; 32:132–138.

27. Evans TA, Seaton SE, Manktelow BN. Quantifying the potential bias when directly comparing standardised mortality ratios for in-unit neonatal mortality. PLoS One. 2013; 8:e61237.

28. Draper ES, Field DJ. Epidemiology of prematurity--how valid are comparisons of neonatal outcomes. Semin Fetal Neonatal Med. 2007; 12:337–343.

29. Terzic S, Heljic S. Assessing mortality risk in very low birth weight infants. Med Arh. 2012; 66:76–79.

30. Bae YM, Bae CW. The changes in the mortality rates of low birth weight infant and very low birth weight infant in Korea over the past 40 years. J Korean Med Sci. 2004; 19:27–31.

31. Choi JH. Milestones of the History of Neonatal Intensive Care in Korea. Neonatal Med. 2013; 20:236–248.

32. Kusuda S, Fujimura M, Uchiyama A, Totsu S, Matsunami K. Research Network Japan. Trends in morbidity and mortality among very-low-birth-weight infants from 2003 to 2008 in Japan. Pediatr Res. 2012; 72:531–538.

33. Su BH, Hsieh WS, Hsu CH, Chang JH, Lien R, Lin CH. Baby Foundation of Taiwan (PBFT). Neonatal outcomes of extremely preterm infants from taiwan: comparison with Canada, Japan, and the USA. Pediatr Neonatol. 2015; 56:46–52.

34. Kusuda S, Fujimura M, Sakuma I, Aotani H, Kabe K, Itani Y, Ichiba H, Matsunami K, Nishida H, Neonatal Research. Morbidity and mortality of infants with very low birth weight in Japan: center variation. Pediatrics. 2006; 118:e1130–e1138.

35. Shim JW, Kim MJ, Kim EK, Park HK, Song ES, Lee SM, Lee JH, Jin HS, Kim ES, Chang YS, et al. The impact of neonatal care resources on regional variation in neonatal mortality among very low birthweight infants in Korea. Paediatr Perinat Epidemiol. 2013; 27:216–225.

36. Arnold C, Tyson JE. Outcomes following periviable birth. Semin Perinatol. 2014; 38:2–11.

37. Upadhyay RP, Krishnan A, Rai SK, Chinnakali P, Odukoya O. Need to focus beyond the medical causes: a systematic review of the social factors affecting neonatal deaths. Paediatr Perinat Epidemiol. 2014; 28:127–137.

38. Rossen LM, Schoendorf KC. Trends in racial and ethnic disparities in infant mortality rates in the United States, 1989-2006. Am J Public Health. 2014; 104:1549–1556.

39. Goldstein RF, Cotten CM, Shankaran S, Gantz MG, Poole WK. Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Influence of gestational age on death and neurodevelopmental outcome in premature infants with severe intracranial hemorrhage. J Perinatol. 2013; 33:25–32.

40. Ishii N, Kono Y, Yonemoto N, Kusuda S, Fujimura M, Neonatal Research. Outcomes of infants born at 22 and 23 weeks' gestation. Pediatrics. 2013; 132:62–71.