J Korean Med Sci.  2022 May;37(20):e162. 10.3346/jkms.2022.37.e162.

Growth Pattern With Morbidities From Birth to 5 Years of Age in Very Low Birth Weight Infants: Comparison of the Korean National Network and National Health Insurance Service

• Lim J
• Yoon SJ
• Shin JE
• Han JH
• Lee SM
• Eun HS
• Park MS
• Park KI

• KMID: 2530105
• DOI: http://doi.org/10.3346/jkms.2022.37.e162

Abstract

Background
Long-term growth data of very low birth weight (VLBW) infants are currently collected in the Korean Neonatal Network (KNN) and National Health Insurance Service (NHIS) database. However, variance in the number of infants, check-up time, and check-up parameters led to decreased credibility of cumulated data. We aimed to compare the data on serial growth outcomes by major morbidities from birth to 5 years in VLBW infants between the KNN and NHIS databases.
Methods
We combined the NHIS and KNN data of VLBW infants born between 2013 and 2015. The check-up times in the NHIS database were at 4–6, 9–12, 18–24, 30–36, 42–48, and 54–60 months of age, whereas in the KNN were at 18–24 months of corrected age and at 36 months of age. Result: Among 8,864 VLBW infants enrolled based on the birth certificates from the Statistics Korea, 6,086 infants (69%) were enrolled in the KNN, and 5,086 infants (57%) participated in the NHIS health check-up. Among 6,068 infants, 3,428 infants (56%) were enrolled at a corrected age of 18–24 months and 2,572 infants (42%) were enrolled at a chronological age of 33–36 months according to the KNN follow-up registry. However, based on the national birth statistics data, the overall follow-up rate of the KNN at 36 months of age was as low as 29%. The NHIS screening rate was lower at first (23%); however, it increased over time to exceed the KNN follow-up rate. Growth failure (weight under 10th percentile) at corrected ages of 18–24 months and 36 months were more common in the NHIS than KNN (42% vs. 20%, 37% vs. 34.5%). Infants with bronchopulmonary dysplasia and periventricular leukomalacia showed similar rates of growth failure at 2 years but varying rates at 3 years between the KNN and NHIS.
Conclusion
By integrating the KNN and NHIS data indirectly at continuous time points according to morbidities, we found that there are discontinuities and discrepancies between the two databases among VLBW infants. Establishing an integrated system by patient level linking the KNN and NHIS databases can lead to better understanding and improved neonatal outcomes in VLBW infants in Korea.

Keyword

Very Low Birth Weight; Prematurity; Korean Neonatal Network; National Health Insurance Service; Integration

Figure

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  Fig. 1 Follow up rate (%) of the KNN and NHIS data. The number of very low birth weight infants at birth and discharge is based on the KNN registry.KNN = Korean Neonatal Network, NHIS = National Health Insurance Service.

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  Fig. 2 Comparison of incidence of growth failure between the KNN and NHIS data. (A) Comparisons made in very low birth weight, (B) in extremely low birth weight, (C) and in the infants with birth weight 1,000–1,500 g.Growth failure at birth and discharge is defined as the weight below 10th percentiles according to the KNN registry.KNN = Korean Neonatal Network, NHIS = National Health Insurance Service.

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  Fig. 3 Comparison of incidence of BPD and PVL between the KNN and NHIS data. (A) BPD and (B) PVL.BPD = bronchopulmonary dysplasia, PVL = periventricular leukomalacia, KNN = Korean Neonatal Network, NHIS = National Health Insurance Service.

• 

  Fig. 4 Comparison of growth patterns and morbidities between the KNN and NHIS data. (A) Weight percentile of infants with BPD and (B) weight percentile of infants with PVL.KNN = Korean Neonatal Network, NHIS = National Health Insurance Service, BPD = bronchopulmonary dysplasia, PVL = periventricular leukomalacia.

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