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

Need for national guidance regarding proactive care of infants born at 22-23 weeks' gestation

With recent rapid improvements in neonatal intensive care, the limit of viability has shifted downward to 22-23 weeks' gestation. The younger the gestational age of preterm infants, the higher the risk of survival despite severe neurodevelopmental impairments. For infants born at 22-23 weeks' gestation, the limit of viability, neurodevelopmental outcomes, and survival rates may be determined by the quality of proactive care. Owing to the high risk of severe neurodevelopmental impairment in 22-23 weeks' gestation, proactive care is sometimes withheld according to ethical or legal considerations, and there are significant differences in the provision of proactive care and survival rates across countries or institutions. Additionally, there are differing or even lacking guidelines regarding the care of these infants across countries and institutions. Japan and Sweden are countries with well-established national guidance and proactive care for infants born at 22-23 weeks' gestation, resulting in higher survival rates among them. In Korea, where there is an extreme shortage of neonatologists, maternal transfer before delivery at 22-23 weeks' gestation to high-activity regions with appropriate neonatal intensive care unit resources, such as adequate personnel and facilities similar to the centralized care model seen in Sweden, is crucial for improving the survival rates of infants born at 22-23 weeks' gestation. The survival of these infants largely depends on the quality of proactive care provided. This rate is not static and can be improved through proactive care based on national guidance and the implementation of enhanced neonatal intensive care practices, including centralization of care.

Unveiling the Emerging Role of Extracellular Vesicle-Inflammasomes in Hyperoxia-Induced Neonatal Lung and Brain Injury

Extremely premature infants are at significant risk for developing bronchopulmonary dysplasia (BPD) and neurodevelopmental impairment (NDI). Although BPD is a predictor of poor neurodevelopmental outcomes, it is currently unknown how BPD contributes to brain injury and long-term NDI in pre-term infants. Extracellular vesicles (EVs) are small, membrane-bound structures released from cells into the surrounding environment. EVs are involved in inter-organ communication in diverse pathological processes. Inflammasomes are large, multiprotein complexes that are part of the innate immune system and are responsible for triggering inflammatory responses and cell death. Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is pivotal in inflammasome assembly and activating inflammatory caspase-1. Activated caspase-1 cleaves gasdermin D (GSDMD) to release a 30 kD N-terminal domain that can form membrane pores, leading to lytic cell death, also known as pyroptosis. Activated caspase-1 can also cleave pro-IL-1β and pro-IL-18 to their active forms, which can be rapidly released through the GSDMD pores to induce inflammation. Recent evidence has emerged that activation of inflammasomes is associated with neonatal lung and brain injury, and inhibition of inflammasomes reduces hyperoxia-induced neonatal lung and brain injury. Additionally, multiple studies have demonstrated that hyperoxia stimulates the release of lung-derived EVs that contain inflammasome cargos. Adoptive transfer of these EVs into the circulation of normal neonatal mice and rats induces brain inflammatory injury. This review focuses on EV-inflammasomes' roles in mediating lung-to-brain crosstalk via EV-dependent and EV-independent mechanisms critical in BPD, brain injury, and NDI pathogenesis. EV-inflammasomes will be discussed as potential therapeutic targets for neonatal lung and brain injury.

Point prevalence, characteristics and treatment variations for preterm infants with bronchopulmonary dysplasia in China: a 'snapshot' study

OBJECTIVE

The incidence of bronchopulmonary dysplasia (BPD) is increasing, but data on its prevalence and management variations remain insufficient in China. The study aims to investigate its point prevalence and variations in BPD care.

SETTING, PATIENTS AND INTERVENTIONS

A multicentre cross-sectional study was conducted in 37 NICUs. 'Snapshot' clinical data on 18 June 2021 for individual patients born at <32 weeks gestation age (GA) were collected. BPD was defined based on the National Institute of Child Health and Human Development (NICHD) 2001 criteria and two newer criteria (NICHD 2018 and Jensen 2019).

RESULTS

A total of 1044 infants born at <32 weeks GA were included, of which 72% were born at ≥28 weeks GA and 95.8% were born at ≥750 g. At the time of 'snapshot', 563 were ≥28 days old and 281 were ≥36 weeks postmenstrual age (PMA). The prevalence of BPD was 78.2% per NICHD 2001 definition. Infants with BPD were more likely to be born earlier with a lower birth weight and to have complications. Among infants who reached 36 weeks PMA, the point prevalence and severity of BPD differed across BPD definitions. Respiratory support and treatments for BPD also significantly varied.

CONCLUSION

Point prevalence of BPD is remarkably high in China. The prevalence of BPD was lowest according to the NICHD 2018 definition, whereas the NICHD 2001 definition classified most patients with severe BPD. We found infants with BPD have more complications and significant differences in BPD treatments between centres. Efforts to prevent BPD and standardise care are warranted in China.

Strategies for the prevention of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common morbidity affecting preterm infants and is associated with substantial long-term disabilities. The pathogenesis of BPD is multifactorial, and the clinical phenotype is variable. Extensive research has improved the current understanding of the factors contributing to BPD pathogenesis. However, effectively preventing and managing BPD remains a challenge. This review aims to provide an overview of the current evidence regarding the prevention of BPD in preterm infants, offering practical insights for clinicians.

Beyond Legal Boundaries: Public and Clinician Perspectives on Treatment Withdrawal in Infants With Poor Neurological Prognosis

BACKGROUND

Despite medical advancements in neonatal survival rates, many children have poor neurological outcomes. Because the law in Korea restricts the withdrawal of life-sustaining treatment to only cases of imminent death, treatment discontinuation may not be an option, even in patients with poor neurological prognosis. This study investigated the opinions of the general population and clinicians regarding life-sustaining treatment withdrawal in such cases using hypothetical scenarios.

METHODS

We conducted a cross-sectional study on the general population and clinicians using a web-based questionnaire. The sample of the general population from an online panel comprised 500 individuals aged 20-69 years selected by quota sampling. The clinician sample comprised 200 clinicians from a tertiary university hospital. We created hypothetical vignettes and questionnaire items to assess attitudes regarding mechanical ventilation withdrawal for an infant at risk of poor neurological prognosis due to birth asphyxia at 2 months and 3 years after the incidence.

RESULTS

Overall, 73% of the general population and 74% of clinicians had positive attitudes toward mechanical ventilator withdrawal at 2 months after birth asphyxia. The proportion of positive attitudes toward mechanical ventilator withdrawal was increased in the general population (84%, P < 0.001) and clinicians (80.5%, P = 0.02) at 3 years after birth asphyxia. Religion, spirituality, the presence of a person with a disability in the household, and household income were associated with the attitudes of the general population. In the multivariable logistic regression analysis of the general population, respondents living with a person with a disability or having a disability were more likely to find the withdrawal of the ventilator at 2 months and 3 years after birth asphyxia not permissible. Regarding religion, respondents who identified as Christians were more likely to find the ventilator withdrawal at 2 months after birth asphyxia unacceptable.

CONCLUSION

The general population and clinicians shared the perspective that the decision to withdraw life-sustaining treatment in infants with a poor neurological prognosis should be considered before the end of life. A societal discussion about making decisions centered around the best interest of pediatric patients is warranted.

Factors affecting length of stay according to bronchopulmonary dysplasia severity: a nationwide cohort study in Korea

BACKGROUND

Longer hospitalizations for preterm infants with bronchopulmonary dysplasia (BPD) delay developmental outcomes, increase the risk for hospital-acquired complications, and exert a substantial socioeconomic burden. This study aimed to identify factors associated with an extended length of stay (LOS) at different levels of severity of BPD.

METHODS

A cohort study was conducted using the Korean Neonatal Network registry of very low birth weight infants with BPD between 2013 and 2017 through retrospective analysis.

RESULTS

A total of 4263 infants were diagnosed with BPD. For mild BPD, infants requiring surgical treatment for patent ductus arteriosus needed a longer LOS [eadjusted β coefficients (adj β) 1.041; 95% confidence interval (CI): 0.01-0.08] and hydrocephalus (eadj β 1.094; 95% CI 0.01-0.17). In moderate BPD, infants administered steroids or with intraventricular hemorrhage required a longer LOS (eadj β 1.041; 95% CI 0.00-0.07 and eadj β 1.271; 95% CI 0.11-0.38, respectively). In severe BPD, infants with comorbidities required a longer LOS: pulmonary hypertension (eadj β 1.174; 95% CI 0.09-0.23), administrated steroid for BPD (eadj β 1.116; 95% CI 0.07-0.14), sepsis (eadj β 1.062; 95% CI 0.01-0.11), patent ductus arteriosus requiring surgical ligation (eadj β 1.041; 95% CI 0.00-0.08), and intraventricular hemorrhage (eadj β 1.016; 95% CI 0.05-0.26). Additionally, the higher the clinical risk index score, the longer the LOS needed for infants in all groups.

CONCLUSIONS

The factors affecting LOS differed according to the severity of BPD. Individualized approaches to reducing LOS may be devised using knowledge of the various risk factors affecting LOS by BPD severity.

Delivery room resuscitation intensity and associated neonatal outcomes of 24+0-31+6 weeks' preterm infants in China: a retrospective cross-sectional study

BACKGROUND

The aim of this study was to review current delivery room (DR) resuscitation intensity in Chinese tertiary neonatal intensive care units and to investigate the association between DR resuscitation intensity and short-term outcomes in preterm infants born at 24+0-31+6 weeks' gestation age (GA).

METHODS

This was a retrospective cross-sectional study. The source population was infants born at 24+0-31+6 weeks' GA who were enrolled in the Chinese Neonatal Network 2019 cohort. Eligible infants were categorized into five groups: (1) regular care; (2) oxygen supplementation and/or continuous positive airway pressure (O2/CPAP); (3) mask ventilation; (4) endotracheal intubation; and (5) cardiopulmonary resuscitation (CPR). The association between DR resuscitation and short-term outcomes was evaluated by inverse propensity score-weighted logistic regression.

RESULTS

Of 7939 infants included in this cohort, 2419 (30.5%) received regular care, 1994 (25.1%) received O2/CPAP, 1436 (18.1%) received mask ventilation, 1769 (22.3%) received endotracheal intubation, and 321 (4.0%) received CPR in the DR. Advanced maternal age and maternal hypertension correlated with a higher need for resuscitation, and antenatal steroid use tended to be associated with a lower need for resuscitation (P < 0.001). Severe brain impairment increased significantly with increasing amounts of resuscitation in DR after adjusting for perinatal factors. Resuscitation strategies vary widely between centers, with over 50% of preterm infants in eight centers requiring higher intensity resuscitation.

CONCLUSIONS

Increased intensity of DR interventions was associated with increased mortality and morbidities in very preterm infants in China. There is wide variation in resuscitative approaches across delivery centers, and ongoing quality improvement to standardize resuscitation practices is needed.

Outcomes at 18-24 Months of Infants with Birth Weight under 500 g Born in Korea during 2013-2017: A Nationwide Cohort Study

INTRODUCTION

This study aimed to investigate the outcomes of infants at 18-24 months born in the Korean Neonatal Network with a birth weight <500 g.

METHODS

The anthropometric and neurodevelopmental data of infants with a birth weight <500 g at a gestational age of ≥22 weeks who were registered in the Korean Neonatal Network 2013-2017 and followed up at a corrected age of 18-24 months were reviewed. Neurodevelopmental impairment was defined as the presence of any of the following: (1) cerebral palsy; (2) severe visual impairment; (3) hearing impairment; or (4) cognitive impairment. Cognitive impairment was defined as (1) a Bayley Scales of Infant Development-II Mental Development Index score <70; and (2) Bayley Scales of Infant and Toddler Development-III Cognitive and Language Composite scores <85. Cognitive testing was performed for infants with suspected problems upon clinician's referral to developmental specialists.

RESULTS

At a median corrected age of 20 months, 26/52 (50%) of included infants had neurodevelopmental impairment. Cerebral palsy, severe visual impairment, wearing of glasses, hearing impairment, and cognitive impairment occurred in 22%, 0%, 8%, 5%, and 57% of the included infants, respectively. The proportions of infants with <2 standard deviations of weight, length, and head circumference were 54%, 52%, and 56%, respectively. The majority (70%) of infants were rehospitalized, and the most common cause was respiratory problems.

CONCLUSION

Half of infants with a birth weight <500 g in Korea may exhibit neurodevelopmental impairment and growth retardation at a corrected age of 18-24 months. Multidisciplinary follow-up along with continuous rehabilitation will be needed to improve neurological and physical development in this special population.

Risk factors for bronchopulmonary dysplasia infants with respiratory score greater than four: a multi-center, prospective, longitudinal cohort study in China

Bronchopulmonary dysplasia (BPD) is the most common complication of prematurity involving both pre- and post-natal factors. A large, prospective, longitudinal cohort study was conducted to determine whether inflammation-related factors are associated with an increased risk of BPD in preterm infants who were born at a gestational age < 32 weeks, < 72 h after birth and respiratory score > 4. The study included infants from 25 participating hospitals in China between March 1, 2020 and March 31, 2022. The primary outcomes were BPD and severity of BPD at 36 weeks post-menstrual age. A total of 1362 preterm infants were enrolled in the study. After exclusion criteria, the remaining 1088 infants were included in this analysis, of whom, 588 (54.0%) infants were in the BPD group and 500 (46.0%) were in the non-BPD group. In the BPD III model, the following six factors were identified: birth weight (OR 0.175, 95% CI 0.060-0.512; p = 0.001), surfactant treatment (OR 8.052, 95% CI 2.658-24.399; p < 0.001), mean airway pressure (MAP) ≥ 12 cm H2O (OR 3.338, 95% CI 1.656-6.728; p = 0.001), late-onset sepsis (LOS) (OR 2.911, 95% CI 1.514-5.599; p = 0.001), ventilator-associated pneumonia (VAP) (OR 18.236, 95% CI 4.700-70.756; p < 0.001) and necrotizing enterocolitis (NEC) (OR 2.725, 95% CI 1.182-6.281; p = 0.019). Premature infants remained at high risk of BPD and with regional variation. We found that post-natal inflammation-related risk factors were associated with an increased risk of severe BPD, including LOS, VAP, NEC, MAP ≥ 12 cm H2O and use of surfactant.

How to screen the cervix and reduce the risk of spontaneous preterm birth in asymptomatic women without a prior preterm birth

Preterm birth (PTB) is a leading cause of perinatal morbidity and mortality globally. PTB rates have increased in South Korea despite reduction in birth rates. A history of PTB is a strong predictor of subsequent PTB and screening of cervical length between 16 0/7 weeks and 24 0/7 weeks of gestation is recommended in women with a singleton pregnancy and a prior spontaneous PTB. However, the prediction and prevention of spontaneous PTBs in women without a prior PTB remain a matter of debate. The scope of this review article comprises cervical screening and prevention strategies for PTB in asymptomatic women without a prior PTB, based on recent evidence and guidelines.

Artificial Intelligence-Driven Respiratory Distress Syndrome Prediction for Very Low Birth Weight Infants: Korean Multicenter Prospective Cohort Study

BACKGROUND

Respiratory distress syndrome (RDS) is a disease that commonly affects premature infants whose lungs are not fully developed. RDS results from a lack of surfactant in the lungs. The more premature the infant is, the greater is the likelihood of having RDS. However, even though not all premature infants have RDS, preemptive treatment with artificial pulmonary surfactant is administered in most cases.

OBJECTIVE

We aimed to develop an artificial intelligence model to predict RDS in premature infants to avoid unnecessary treatment.

METHODS

In this study, 13,087 very low birth weight infants who were newborns weighing less than 1500 grams were assessed in 76 hospitals of the Korean Neonatal Network. To predict RDS in very low birth weight infants, we used basic infant information, maternity history, pregnancy/birth process, family history, resuscitation procedure, and test results at birth such as blood gas analysis and Apgar score. The prediction performances of 7 different machine learning models were compared, and a 5-layer deep neural network was proposed in order to enhance the prediction performance from the selected features. An ensemble approach combining multiple models from the 5-fold cross-validation was subsequently developed.

RESULTS

Our proposed ensemble 5-layer deep neural network consisting of the top 20 features provided high sensitivity (83.03%), specificity (87.50%), accuracy (84.07%), balanced accuracy (85.26%), and area under the curve (0.9187). Based on the model that we developed, a public web application that enables easy access for the prediction of RDS in premature infants was deployed.

CONCLUSIONS

Our artificial intelligence model may be useful for preparations for neonatal resuscitation, particularly in cases involving the delivery of very low birth weight infants, as it can aid in predicting the likelihood of RDS and inform decisions regarding the administration of surfactant.

Impact of Cerebellar Injury on Neurodevelopmental Outcomes in Preterm Infants With Cerebral Palsy

OBJECTIVE

We aimed to analyze brain imaging findings and neurodevelopmental outcomes of preterm infants diagnosed with cerebral palsy.

DESIGN

Brain magnetic resonance imaging of preterm infants born between 23 and 32 wks' gestation and diagnosed with cerebral palsy at 2 yrs of corrected age were evaluated. Brain lesions were categorized as periventricular leukomalacia, intraventricular hemorrhage, and cerebellar hemorrhage and graded by the severity. Neurodevelopmental outcomes were assessed using the Bayley Scales of Infant and Toddler Development, Third Edition, at 18-24 mos corrected age, and the Korean Ages and Stages Questionnaire at 18 and 24 mos of corrected age.

RESULTS

Cerebral palsy was found in 38 children (6.1%) among 618 survivors. Cerebellar injury of high-grade cerebellar hemorrhage and/or atrophy accounted for 25%. Among patients with supratentorial lesions, those having cerebellar injury showed significantly lower scores on each Korean Ages and Stages Questionnaire domain except gross motor than patients without cerebellar injury. They also revealed a high proportion of patients below the cutoff value of Korean Ages and Stages Questionnaire in language, fine motor, and problem-solving domains ( P < 0.05) and lower Bayley Scales of Infant and Toddler Development, Third Edition, language composite scores ( P = 0.038).

CONCLUSIONS

Poor neurodevelopmental outcomes other than motor function were associated with cerebellar injury. Evaluation of the cerebellum may help predict functional outcomes of patients with cerebral palsy.

Prevalence of asthma in preterm and associated risk factors based on prescription data from the Korean National Health Insurance database

We retrospectively analyzed National Health Insurance claims data (January 2002-December 2018) to determine the asthma prevalence and risk factors among preterm infants born in Korea. Patients with asthma were defined as those with a history of asthma medication prescriptions at least twice per year with International Classification of Diseases, Tenth Edition codes J45 and J46. We enrolled 99,139 preterm infants. The prevalence of asthma among preterm and term infants was 32.7% and 26.9%, 21.2% and 19.1%, 6.7% and 5.9%, 2.0%, and 1.6%, and 2.4% and 1.6% at 2, 5, 10, 15, and 16 years of age, respectively. The relative risk (RR) of asthma in preterm infants was 1.1-fold that in female preterm infants. The RR of asthma medication prescriptions for infants with extreme prematurity was 1.92-fold that of infants with moderate/late pre-term status. Among preterm with bronchopulmonary dysplasia (BPD) and respiratory distress syndrome (RDS) without comorbidities, the RRs for the number of asthma medication prescriptions were 1.34 and 1.06, respectively. This study revealed a higher prevalence of asthma among preterm infants than that in term infants. Male sex, extreme prematurity, BPD, and RDS were identified as risk factors for asthma medication prescriptions in preterm infants.

Association Between Retinopathy of Prematurity in Very-Low-Birth-Weight Infants and Neurodevelopmental Impairment

PURPOSE

To evaluate the impact of retinopathy of prematurity (ROP) severity and the treatment of very-low-birth-weight infants (VLBWIs) on neurodevelopmental impairment in early childhood.

DESIGN

Prospective cohort study.

METHOD

This was a prospective cohort study. The data were obtained from the Korean Neonatal Network (KNN), a nationwide registry for VLBWIs. Infants who were born from 2013 to 2015 and underwent ROP evaluation at birth and neurodevelopmental examinations at corrected ages of 18 to 24 months were included in the study. Infants with a history of meningitis or severe congenital anomalies were excluded. The VLBWI patients were grouped into no ROP, no treatment-requiring ROP (non-TR-ROP), and treatment-requiring ROP (TR-ROP) groups. Neurodevelopmental impairment was defined as participants who had at least 1 developmental problem according to the Bayley Scales of Infant and Toddler Development-2nd Edition (Bayley-II; <70), Bayley Scales of Infant and Toddler Development-3rd Edition (Bayley-III; <70), and Korean Developmental Screening Test (K-DST) tests (below -1 SD), and the Korean Ages and Stages Questionnaire (K-ASQ) (below the threshold) and Gross Motor Function Classification System (GMFCS; at level 2 or above). Multivariable logistic regression analysis was performed to evaluate the association between ROP and neurodevelopmental impairment.

RESULT

Among 3132 infants, 1093 (34.9%) had ROP. Among the ROP infants, 644 were not treated for ROP (non-TR-ROP group) and 449 received ROP treatments (TR-ROP group). The patients in the TR-ROP group had an increased risk of developing neurodevelopmental problems compared to those in the no ROP group (odds ratio [OR] = 1.72, 95% CI = 1.33-2.21). The TR-ROP group had a higher risk of all 3 types of neurodevelopmental problems: mental (OR = 1.62, 95% CI = 1.25-2.09), social (OR = 1.62, 95% CI = 1.12-2.09), and motor (OR = 1.69, 95% CI = 1.31-2.18). The risk of neurodevelopmental problems in patients treated with laser therapy did not differ from that in patients treated with anti-vascular endothelial growth factor (anti-VEGF) therapy (OR = 1.17, 95% CI = 0.73-1.88).

CONCLUSION

ROP was independently associated with neurodevelopmental impairment in early childhood. The type of ROP treatment (anti-VEGF or laser treatment) did not affect neurodevelopmental impairment in patients in the TR-ROP group.

Cystic Periventricular Leukomalacia Worsens Developmental Outcomes of Very-Low-Birth Weight Infants with Intraventricular Hemorrhage-A Nationwide Cohort Study

Cystic periventricular leukomalacia (cPVL) is a major brain injury involving periventricular white matter that leads to neurodevelopmental impairment in very-low-birth weight (VLBW) infants. We investigated the neurodevelopmental outcomes (motor, cognition, visual, and hearing) of 5734 VLBW infants born between 2013 and 2019 and enrolled in the Korean Neonatal Network. Cranial ultrasound results were stratified by the presence of cPVL and severity of intraventricular hemorrhage (IVH) (no, low-grade [I/II], high-grade [III]). Neurodevelopmental impairment was evaluated using cerebral palsy for motor and Bayley Scales of Infant Development for cognition. cPVL was associated with motor, cognitive, and visual impairments in those without IVH and with low-grade IVH in pairwise comparisons (Cochran−Mantel−Haenszel p < 0.001). Conversely, cPVL was non-significantly correlated with cognitive impairment in high-grade IVH. In regression models adjusted for neonatal variables, isolated cPVL was strongly associated with motor (22.04; 11.39−42.63) and cognitive (3.10; 1.54−6.22) impairments. This study underlines the overall considerable significance of cPVL on NDI with divergent impacts depending on the severity of IVH and developmental indices.

The growth rates and influencing factors of preterm and full-term infants: A birth cohort study

This study aimed to explore the growth rates and influencing factors of the length and weight of preterm and full-term infants in the urban areas of Hubei province to provide a reference for child health and related clinical fields. A birth cohort study was used to analyze the growth rates and influencing factors of the length and weight of preterm and full-term infants using a multivariate regression analysis. The growth rates of the length and weight of preterm infants were significantly lower than those of full-term infants from birth to 3 months of age (P < .05), and gradually caught up to the level of full-term infants after 3 months of age (P > .05). Meanwhile, there were some influencing factors that had significant differences by their contribution to the growth rates of the length and weight of preterm and full-term infants. This study proposed that perinatal factors were attached more importance to the growth rates of preterm infants in the urban areas of Hubei province.

Serial Short-Term Outcomes of Very-Low-Birth-Weight Infants in the Korean Neonatal Network From 2013 to 2020

BACKGROUND

We aimed to determine the current survival rate and short-term outcomes of very-low-birth-weight infants (VLBWIs) in Korea, as well as whether the survival rate and short-term outcomes have improved over time since 2013, which was when the Korean Neonatal Network (KNN) was launched.

METHODS

This study used data from the annual reports of the KNN from 2013 to 2020. A total of 16,351 VLBWIs born at gestational age (GA) ≥ 22 weeks between January 1, 2013, and December 31, 2020, and who were registered in the KNN were enrolled. Serial outcomes were analyzed according to era (2013-14, 2015-16, 2017-18, and 2019-20).

RESULTS

More mothers delivered by cesarean section, had diabetes or hypertension during their pregnancy, and received antenatal steroids when analyzed by era. Fewer infants were intubated at birth and had air leaks when analyzed by era. The overall survival rate of VLBWIs between 2013 and 2020 was 87%. The rate of respiratory distress syndrome was 77% and that of bronchopulmonary dysplasia was 32% between 2013 and 2020. The rates of intraventricular hemorrhage (grade ≥ 3), periventricular leukomalacia, and sepsis decreased over time. The survival rate of infants with a GA of 26 weeks has improved serially according to era.

CONCLUSION

Since the launch of the KNN in 2013, the survival rates of infants with GA 26 weeks and short-term outcomes have improved, which implies a quality improvement in antenatal and delivery room care. Further studies on the long-term neurodevelopmental outcomes of these KNN registrants are warranted.

Medical Utilization and Costs in Preterm Infants in the First 6 Years of Life After Discharge From Neonatal Intensive Care Unit: A Nationwide Population-Based Study in Korea

BACKGROUND

The improvement in the survival rate of preterm infants has paradoxically raised the risk of morbidities in childhood. Our objectives were to assess the medical utilization and costs in preterm infants following discharge from the neonatal intensive care unit in the first 6 years of life.

METHODS

We conducted a population-based study using the National Health Information Database (2011-2017) provided by the Korean National Health Insurance Service (NHIS). A total of 361,190 children born in Korea between January 1 and December 31, 2011 were divided into four groups according to the gestational age at birth: extremely preterm (less than 28 weeks), very preterm (28-31 weeks), moderate to late preterm (32-36 weeks), and full term (37-41 weeks). The cumulative number of outpatient visits, cumulative length of hospital stay, rate of hospital and intensive care unit admissions, and cumulative medical costs for inpatients and outpatients were compared for each gestational age group.

RESULTS

Earlier gestational age was significantly associated with an increased risk of the cumulative number of outpatient visits, cumulative length of hospital stay, and rate of hospital and intensive care unit admissions for the first 6 years of life. The mean cumulative inpatient and outpatient costs per child significantly decreased with increasing gestational age. When assessed based on population size, the total cumulative medical costs were highest for moderate to late preterm children.

CONCLUSION

Earlier gestational age was strongly associated with increased healthcare resource utilization and medical costs. Our findings on the potential long-term socioeconomic impact on public health are expected to aid the development of future health care policies for preterm children.

Perinatal Outcomes According to Accessibility to Maternal-Fetal and Neonatal Intensive Care Units by Region in Korea

BACKGROUND

Herein, we aimed to evaluate the maternal mortality ratio and perinatal mortality rate for different perinatal medical care service areas (PMCSAs), which were established by considering their geographical accessibility to maternal-fetal intensive care units (MFICUs) and neonatal intensive care units (NICUs), and to compare the PMCSAs according to their accessibility to these perinatal care services.

METHODS

Based on the 70 hospital service areas (HSAs) across the country confirmed through the Dartmouth Atlas methodology analysis and gathering of expert opinions, the PMCSAs were designated by merging HSAs without MFICUs and NICUs to the nearest HSA that contained MFICUs and NICUs, based on which MFICU and NICU could be reached within the shortest amount of time from population-weighted centroids in HSAs. PMCSAs where 30% or more of the population could not access MFICUs and NICUs within 60 minutes were identified using the service module ArcGIS and were defined as having access vulnerability.

RESULTS

Thirty-three of 70 HSAs in the country did not contain MFICUs and NICUs, and 39 PMCSAs were finally derived by merging 70 HSAs. Ten of 39 PMCSAs (25.6%) were classified as having access vulnerability to MFICUs and NICUs. The national maternal mortality ratio was 9.42, with the highest ratio seen in the region of Wonju (25.86) and the lowest in Goyang (2.79). The national perinatal mortality rate was 2.86, with the highest and lowest rates observed in the Gunsan (4.04) and Sejong (1.99) regions, respectively. The perinatal mortality rates for areas vulnerable and invulnerable to maternal and neonatal healthcare accessibility were 2.97 and 2.92, respectively, but there was no statistically significant difference in this rate (P = 0.789). The maternal mortality ratio for areas vulnerable and invulnerable to maternal and neonatal healthcare accessibility were 14.28 and 9.48, respectively; this ratio was significantly higher in areas vulnerable to accessibility (P = 0.022).

CONCLUSION

Of the PMCSAs across the country, 25.6% (10/39) were deemed to be vulnerable to MFICU and NICU accessibility. There was no difference in the perinatal mortality rate between the vulnerable and invulnerable areas, but the maternal mortality ratio in vulnerable areas was significantly higher than that in invulnerable areas.

Survival and Morbidities in Infants with Birth Weight Less than 500 g: a Nationwide Cohort Study

BACKGROUND

This study aimed to investigate the survival and morbidities of infants in the Korean Neonatal Network (KNN) with birth weight (BW) < 500 g.

METHODS

The demographic and clinical data of 208 live-born infants with a BW < 500 g at a gestational age of ≥ 22 weeks who were treated in the neonatal intensive care units of the KNN between 2013 and 2017 were reviewed.

RESULTS

The survival rate of the infants was 28%, with a median gestational age and BW of 243/7 weeks (range, 220/7-336/7) and 440 g (range, 220-499), respectively. Multivariable Cox proportional hazards analysis demonstrated that survival to discharge was associated with longer gestation, higher BW, female sex, singleton gestation, use of any antenatal corticosteroids, and higher Apgar scores at 5 minutes. The overall survival rates were significantly different between the BW categories of < 400 g and 400-499 g. However, there was no significant difference in the incidence of any morbidity between the BW groups. Half of the deaths of infants with BW < 500 g occurred within a week of life, mainly due to cardiopulmonary and neurologic causes. The major causes of death in infants after 1 week of age were infection and gastrointestinal disease. Among the surviving infants, 79% had moderate to severe bronchopulmonary dysplasia, 21% underwent surgical ligation of patent ductus arteriosus, 12% had severe intraventricular hemorrhage (grade III-IV), 38% had sepsis, 9% had necrotizing enterocolitis (stage ≥ 2), and 47% underwent laser treatment for retinopathy of prematurity. The median length of hospital stay was 132 days (range, 69-291), and 53% required assistive devices at discharge.

CONCLUSION

Despite recent advances in neonatal intensive care, the survival and morbidity rates of infants with BW < 500 g need further improvement.

Delivery room resuscitation and short-term outcomes of extremely preterm and extremely low birth weight infants: a multicenter survey in North China

Background:

Delivery room resuscitation assists preterm infants, especially extremely preterm infants (EPI) and extremely low birth weight infants (ELBWI), in breathing support, while it potentially exerts a negative impact on the lungs and outcomes of preterm infants. This study aimed to assess delivery room resuscitation and discharge outcomes of EPI and ELBWI in China.

Methods:

The clinical data of EPI (gestational age [GA] <28 weeks) and ELBWI (birth weight [BW] <1000 g), admitted within 72 h of birth in 33 neonatal intensive care units from five provinces and cities in North China between 2017 and 2018, were analyzed. The primary outcomes were delivery room resuscitation and risk factors for delivery room intubation (DRI). The secondary outcomes were survival rates, incidence of bronchopulmonary dysplasia (BPD), and risk factors for BPD.

Results:

A cohort of 952 preterm infants were enrolled. The incidence of DRI, chest compressions, and administration of epinephrine was 55.9% (532/952), 12.5% (119/952), and 7.0% (67/952), respectively. Multivariate analysis revealed that the risk factors for DRI were GA <28 weeks (odds ratio [OR], 3.147; 95% confidence interval [CI], 2.082–4.755), BW <1000 g (OR, 2.240; 95% CI, 1.606–3.125), and antepartum infection (OR, 1.429; 95% CI, 1.044–1.956). The survival rate was 65.9% (627/952) and was dependent on GA. The rate of BPD was 29.3% (181/627). Multivariate analysis showed that the risk factors for BPD were male (OR, 1.603; 95% CI, 1.061–2.424), DRI (OR, 2.094; 95% CI, 1.328–3.303), respiratory distress syndrome exposed to ≥2 doses of pulmonary surfactants (PS; OR, 2.700; 95% CI, 1.679–4.343), and mechanical ventilation ≥7 days (OR, 4.358; 95% CI, 2.777–6.837). However, a larger BW (OR, 0.998; 95% CI, 0.996–0.999), antenatal steroid (OR, 0.577; 95% CI, 0.379–0.880), and PS use in the delivery room (OR, 0.273; 95% CI, 0.160–0.467) were preventive factors for BPD (all P < 0.05).

Conclusion:

Improving delivery room resuscitation and management of respiratory complications are imperative during early management of the health of EPI and ELBWI.

Nationwide incidence and treatment pattern of retinopathy of prematurity in South Korea using the 2007-2018 national health insurance claims data

The aim of this study is to investigate the nationwide incidence and treatment pattern of retinopathy of prematurity (ROP) in South Korea. Using the population-based National Health Insurance database (2007–2018), the nationwide incidence of ROP among premature infants with a gestational age (GA) < 37 weeks (GA < 28 weeks, GA28; 28 weeks ≤ GA < 37 weeks; GA28-37) and the percentage of ROP infants who underwent treatment [surgery (vitrectomy, encircling/buckling); retinal ablation (laser photocoagulation, cryotherapy)] were evaluated. We identified 141,964 premature infants, 42,300 of whom had ROP, with a nationwide incidence of 29.8%. The incidence of ROP in GA28 group was 4.3 times higher than in GA28-37 group (63.6% [2240/3522] vs 28.9% [40,060/138,442], p < 0.001). As for the 12-year trends, the incidence of ROP decreased from 39.5% (3308/8366) in 2007 to 23.5% (2943/12,539) in 2018. 3.0% of ROP infants underwent treatment (25.0% in GA28; 1.7% in GA28-37); 0.2% (84/42,300) and 2.9% (1214/42,300) underwent surgery and retinal ablation, respectively. The overall percentage of ROP infants who underwent treatment has decreased from 4.7% in 2007 to 1.8% in 2018. This first Korean nationwide epidemiological study of ROP revealed a decreased incidence of ROP and a decreased percentage of ROP infants undergoing conventional treatment during a 12-year period.

Trends in Perinatal Practices and Neonatal Outcomes of Very Low Birth Weight Infants during a 16-year Period at NEOCOSUR Centers

OBJECTIVE

To describe trends in mortality, major morbidity, and perinatal care practices of very low birth weight infants born at NEOCOSUR Neonatal Network centers from January 1, 2001, through December 31, 2016.

STUDY DESIGN

A retrospective analysis of prospectively collected data from all inborn infants with a birthweight of 500-1500 g and 23-35 weeks of gestation.

RESULTS

We examined data for 13 987 very low birth weight infants with a mean birth weight of 1081 ± 281 g and a gestational age of 28.8 ± 2.9 weeks. Overall mortality was 26.8% without significant changes throughout the study period. Decreases in early onset sepsis from 6.3% to 2.8% (P <.001), late onset sepsis from 21.1% to 19.5% (P = .002), retinopathy of prematurity from 21.3% to 13.8% (P <.001), and hydrocephalus from 3.8% to 2.4% (P <.001), were observed. The incidence for bronchopulmonary dysplasia decreased from 17.3% to 16% (P = .043), incidence of severe intraventricular hemorrhage was 10.4%, necrotizing enterocolitis 11.1%, and periventricular leukomalacia 3.8%, and did not change over the study period. Administration of antenatal corticosteroids increased from 70.2% to 82.3% and cesarean delivery from 65.9% to 75.4% (P <.001). The use of conventional mechanical ventilation decreased from 67.7% to 63.9% (P <.001) and continuous positive airway pressure use increased from 41.3% to 64.3% (P <.001). Survival without major morbidity increased from 37.4% to 44.5% over the study period (P <.001).

CONCLUSIONS

Progress in perinatal and neonatal care at network centers was associated with an improvement in survival without major morbidity of very low birth weight infants during a 16-year period. However, overall mortality remained unchanged.

Short- and long-term outcomes of very low birth weight infants in Korea: Korean Neonatal Network update in 2019

Korea currently has the world's lowest birth rate but a rapidly inreasing number of preterm infants. The Korean Neonatal Network (KNN), launched by the Korean Society of Neonatology under the support of Korea Centers for Disease Control, has collected population-based data for very low birth weight infants (VLBWIs) born in Korea since 2013. In terms of the short-term outcomes of VLBWIs born from 2013 to 2016 registered in the KNN, the survival rate of all VLBWIs was 86%. Respiratory distress syndrome and bronchopulmonary dysplasia were observed in 78% and 30% of all VLBWIs, respectively. Necrotizing enterocolitis occurred in 7%, while 8% of the VLBWIs needed therapy for retinopathy of prematurity in the neonatal intensive care unit (NICU). Sepsis occurred in 21% during their NICU stay. Intraventricular hemorrhage (grade ≥III) was diagnosed in 10%. In terms of the long-term outcomes for VLBWIs born from 2013 to 2014 registered in the KNN, the post-discharge mortality rate was approximately 1.2%-1.5%, mainly owing to their underlying illness. Nearly half of the VLBWIs were readmitted to the hospital at least once in their first 1-2 years of life, mostly as a result of respiratory diseases. The overall prevalence of cerebral palsy was 6.2%-6.6% in Korea. Bilateral blindness was reported in 0.2%-0.3% of VLBWIs, while bilateral hearing loss was found in 0.8%-1.9%. Since its establishment, the KNN has published annual reports and papers that facilitate the improvement of VLBWI outcome and the formulation of essential healthcare policies in Korea.

Hospitalizations for viral respiratory infections in children under 2 years of age: epidemiology and in-hospital complications

BACKGROUND

Viral respiratory infections (VRIs) are a frequent cause of hospitalization in children under 24 months of age. A history of prematurity or heart disease may be a risk factor for complications in patients hospitalized for VRI. The objective was to describe epidemiological data for children hospitalized for IRV and aged 1 to 24 months and to identify risk factors for the presence of in-hospital complications and mortality over a period of 5 years.

METHODS

This was a cross-sectional study. Patients registered with VRI codes B974, J12, J120-J129X, J168, J17, J171, J178, J20, J203-J209, J21, J210, J211, J218, J219 (based on International Classification of Diseases [ICD-10]) from 2013 to 2017 were included. Three subanalyses were performed to compare [1] patients with pathological history (prematurity, bronchopulmonary dysplasia [BPD] and congenital heart disease [CHD]), [2] diagnoses (pneumonia, acute bronchitis, and acute bronchiolitis), and [3] admission to the pediatric intensive care unit. Days of hospital stay, in-hospital complications, invasive medical procedure and mortality were analyzed.

STATISTICAL ANALYSIS

VRI hospitalization prevalence was described. For comparison between groups, Student's t-test, ANOVA and the Chi2 test were applied. To identify factors related to days of hospital stay, in-hospital complications and mortality, a linear and logistic regression model was performed.

RESULTS

A total of 66,304 hospitalizations were reported. The average age was 14.7 weeks; hospitalization events were higher in winter (39%), followed by autumn (27.3%). A total of 371 (0.56%) patients died. A total of 7068 (10.6%) hospitalized patients with pathological histories were identified. The presence of BPD (coefficient = 1.6), CHD (coefficient = 1.2), diagnosis of pneumonia (coefficient = 1.2), in-hospital complications (coefficient = 2.1) and invasive medical procedures (coefficient = 15.7) were the most common factors that increased the length of hospital stay. Risk factors for in-hospital complications and mortality were invasive medical procedure (OR = 3.3 & 11.7), BPD (OR = 1.8 & 1.6), CHD (OR = 4.6 & 3.4) and diagnosis of pneumonia (OR = 1.8 & 4.2).

CONCLUSIONS

Risk factors for morbidity and mortality in patients hospitalized for VRIs are BPD and CHD, diagnosis of pneumonia and invasive medical procedure.

The Influence of the Variation in Sepsis Rate between Neonatal Intensive Care Units on Neonatal Outcomes in Very-Low-Birth-Weight Infants

Sepsis is commonly known to affect neonatal outcomes. We assessed how much center-to-center variability of the sepsis rate affects the outcomes of very-low-birth-weight infants (VLBWIs). 7,493 VLBWIs registered in the Korean Neonatal Network from 2013 to 2016 were classified into three groups according to the sepsis rate: low sepsis group (LS) < 25^th percentile versus intermediate sepsis group (IS) 25^th–75^th versus high sepsis group (HS) ≥ 75^th. The incidence density of sepsis for the LS, IS, and HS groups were 1.17, 3.17, and 8.88 cases/1,000 person-days. After propensity score matching was done for multiple antenatal and perinatal factors, the odds ratio of death, moderate to severe bronchopulmonary dysplasia and/or death, periventricular leukomalacia, and survival without major morbidities for the HS group were 2.0 (95% confidence interval 1.4–2.8), 1.9 (1.5–2.4), 1.5 (1.1–2.3) and 0.7 (0.5–0.8) when compared with the IS group, and 2.2 (1.6–3.2), 2.3 (1.8–2.9), 2.0 (1.3–2.9), and 0.7 (0.6–0.9) when compared with the LS group. There were no significant differences in those outcomes between the LS and IS groups. Hence, nationwide quality improvements to control the sepsis rate especially in units with a high sepsis rate will be helpful to improve the outcomes of VLBWIs.

Bronchopulmonary dysplasia

In the absence of effective interventions to prevent preterm births, improved survival of infants who are born at the biological limits of viability has relied on advances in perinatal care over the past 50 years. Except for extremely preterm infants with suboptimal perinatal care or major antenatal events that cause severe respiratory failure at birth, most extremely preterm infants now survive, but they often develop chronic lung dysfunction termed bronchopulmonary dysplasia (BPD; also known as chronic lung disease). Despite major efforts to minimize injurious but often life-saving postnatal interventions (such as oxygen, mechanical ventilation and corticosteroids), BPD remains the most frequent complication of extreme preterm birth. BPD is now recognized as the result of an aberrant reparative response to both antenatal injury and repetitive postnatal injury to the developing lungs. Consequently, lung development is markedly impaired, which leads to persistent airway and pulmonary vascular disease that can affect adult lung function. Greater insights into the pathobiology of BPD will provide a better understanding of disease mechanisms and lung repair and regeneration, which will enable the discovery of novel therapeutic targets. In parallel, clinical and translational studies that improve the classification of disease phenotypes and enable early identification of at-risk preterm infants should improve trial design and individualized care to enhance outcomes in preterm infants.