Mortality and morbidity of extremely low birth weight infants in Japan, 2015

Tokuo Miyazawa; Hitomi Arahori; Satoshi Ohnishi; Hromichi Shoji; Atsushi Matsumoto; Yuka Sano Wada; Naoto Takahashi; Toshimitsu Takayanagi; Satoshi Toishi; Ken Nagaya; Hisaya Hasegawa; Masahiro Hayakawa; Mariko Hida; Rie Fukuhara; Yasumasa Yamada; Masahiko Kawai; Kusaka Takashi; Kazuko Wada; Ichiro Morioka; Katsumi Mizuno

doi:10.1111/ped.15493

Mortality and morbidity of extremely low birth weight infants in Japan, 2015

Pediatr Int. 2023 Jan;65(1):e15493. doi: 10.1111/ped.15493.

Authors

Tokuo Miyazawa^{1

2}, Hitomi Arahori^{1

3}, Satoshi Ohnishi^{1

4}, Hromichi Shoji^{1

5}, Atsushi Matsumoto^{1

6}, Yuka Sano Wada^{1

7}, Naoto Takahashi^{1

8}, Toshimitsu Takayanagi^{1

9}, Satoshi Toishi^{1

10}, Ken Nagaya^{1

11}, Hisaya Hasegawa^{1

12}, Masahiro Hayakawa^{1

13}, Mariko Hida^{1

14}, Rie Fukuhara^{1

15}, Yasumasa Yamada^{1

16}, Masahiko Kawai^{1

17}, Kusaka Takashi^{1

18}, Kazuko Wada^{1

19}, Ichiro Morioka^{1

20}, Katsumi Mizuno^{1

2}

Affiliations

¹ The Committee on Neonatal Medicine, Japan Pediatric Society, Tokyo, Japan.
² Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan.
³ Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan.
⁴ Department of Pediatrics, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan.
⁵ Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan.
⁶ Department of Pediatrics, Iwate Medical University School of Medicine, Iwate, Japan.
⁷ Department of Neonatology, National Center for Child Health and Development, Tokyo, Japan.
⁸ Department of Pediatrics, The University of Tokyo Hospital, Tokyo, Japan.
⁹ Department of Pediatrics, National Hospital Organization, Saga National Hospital, Saga, Japan.
¹⁰ Department of Neonatology, Japanese Red Cross Narita Hospital, Chiba, Japan.
¹¹ Division of Neonatology, Center for Maternity and Infant Care, Asahikawa Medical University Hospital, Hokkaido, Japan.
¹² Division of Neonatal Intensive Care, Tokyo Women's Medical University Adachi Medical Center, Tokyo, Japan.
¹³ Division of Neonatology, Center for Maternal-Neonatal Care, Nagoya University Hospital, Nagoya, Japan.
¹⁴ Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
¹⁵ Department of Neonatology, Hiroshima Prefectural Hospital, Hiroshima, Japan.
¹⁶ Department of Perinatal and Neonatal Medicine, Aichi Medical University Hospital, Aichi, Japan.
¹⁷ Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
¹⁸ Department of Pediatrics, Faculty of Medicine, Kagawa University, Kagawa, Japan.
¹⁹ Department of Neonatology, Osaka Women's and Children's Hospital, Osaka, Japan.
²⁰ Department of Pediatrics and Child Health, Nihon University School of Medicine, Tokyo, Japan.

PMID: 36740921
DOI: 10.1111/ped.15493

Abstract

Background: In Japan, the mortality rate of extremely low birth weight (ELBW) infants is notably low in comparison with other developed countries, but the prevalence of chronic lung disease (CLD) and retinopathy of prematurity (ROP) is relatively high. This study aimed to estimate the mortality and morbidity of ELBW infants born in 2015 who were admitted to neonatal intensive care units (NICUs) in Japan and to examine the factors that affected the short-term outcomes of these infants. We also compared the mortality of ELBW infants born in 2005, 2010, and 2015.

Methods: We analyzed the mortality, morbidity, and factors related to short-term outcomes of ELBW infants, using data from 2782 infants born in 2015 and registered at NICUs in Japan.

Results: The mortality rates during NICU stays were 17.0%, 12.0%, and 9.8% for ELBW infants born in 2005, 2010, and 2015, respectively. Among ELBW infants born in 2015, multiple logistic regression analysis showed that short gestational age and low birthweight Z-score contributed to the increased risk of death. Births by cesarean section and antenatal corticosteroid administration were significantly associated with a reduced risk of death. Among infants who survived, CLD was observed in 53.1% and ROP requiring treatment was observed in 30.4%.

Conclusions: Mortality in ELBW infants decreased significantly from 2005 to 2015. As CLD and ROP may affect quality of life and long-term outcomes of infants who survived, prevention strategies and management for these complications are critical issues in neonatal care in Japan.

Keywords: antenatal corticosteroid; cesarean section; extremely low birthweight infant; morbidity; mortality.

MeSH terms

Cesarean Section
Female
Humans
Infant Mortality*
Infant, Extremely Low Birth Weight
Japan / epidemiology
Lung Injury / epidemiology
Male
Morbidity
Prevalence
Quality of Life
Retinopathy of Prematurity / epidemiology