Hyeon-Jong Yang

Dr. Hyeon-Jong Yang

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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 July 2022 in JAMA Network Open
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Journal Article
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KKKyunghoon Kim
Kyunghoon Kim
SJSungsu Jung
Sungsu Jung
MKMina Kim
Mina Kim
SPSuyeon Park
Suyeon Park
HYHyeon-Jong Yang
Hyeon-Jong Yang
ELEun Lee
Eun Lee
Mycoplasma pneumoniae is one of the most common causes of community-acquired pneumonia (CAP) in children, accounting for approximately 30% to 40% of cases.1,2 Some cases of M pneumoniae infection have been considered as a self-limiting disease, whereas other cases of M pneumoniae infection have led to poor clinical outcomes with serious complications.3-6 Mycoplasma pneumoniae lacks a cell wall and is thus resistant to antibiotics targeting the cell walls. Because antibiotics targeting cell walls are not an option for treating M pneumoniae infection, antibiotic treatment options for M pneumoniae infections include those that play a role in the disruption of protein synthesis (eg, macrolides and tetracyclines) and in the inhibition of DNA replication (eg, fluoroquinolones).7 However, tetracyclines and fluoroquinolones have limited use for children because of the lack of information on the safety in this population.8 Therefore, macrolides have been the first choice for treating M pneumoniae infection in children.

12 February 2020 in BMC Infectious Diseases
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PDPneumonia and Respiratory Disease Study Group of Korean Academy of Pediatric Allergy and Respiratory Disease
Pneumonia and Respiratory Disease Study Group of Korean Academy of Pediatric Allergy and Respiratory Disease
ELEun Lee
Eun Lee
CKChul-Hong Kim
Chul-Hong Kim
YLYong Ju Lee
Yong Ju Lee
HKHyo-Bin Kim
Hyo-Bin Kim
HYHyeon-Jong Yang
Hyeon-Jong Yang
Background: Community–acquired pneumonia (CAP) is one of the leading worldwide causes of childhood morbidity and mortality. Its disease burden varies by age and etiology and is time dependent. We aimed to investigate the annual and seasonal patterns in etiologies of pediatric CAP requiring hospitalization. Methods: We conducted a retrospective study in 30,994 children (aged 0–18 years) with CAP between 2010 and 2015 at 23 nationwide hospitals in South Korea. Mycoplasma pneumoniae (MP) pneumonia was clinically classified as macrolide-sensitive MP, macrolide-less effective MP (MLEP), and macrolide-refractory MP (MRMP) based on fever duration after initiation of macrolide treatment, regardless of the results of in vitro macrolide sensitivity tests. Results: MP and respiratory syncytial virus (RSV) were the two most commonly identified pathogens of CAP. With the two epidemics of MP pneumonia (2011 and 2015), the rates of clinical MLEP and MRMP pneumonia showed increasing trends of 36.4% of the total MP pneumonia. In children < 2 years of age, RSV (34.0%) was the most common cause of CAP, followed by MP (9.4%); however, MP was the most common cause of CAP in children aged 2–18 years of age (45.3%). Systemic corticosteroid was most commonly administered for MP pneumonia. The rate of hospitalization in intensive care units was the highest for RSV pneumonia, and ventilator care was most commonly needed in cases of adenovirus pneumonia. Conclusions: The present study provides fundamental data to establish public health policies to decrease the disease burden due to CAP and improve pediatric health.

3 July 2014 in BMC Pulmonary Medicine
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HYHyeon-Jong Yang
Hyeon-Jong Yang
SLSo-Yeon Lee
So-Yeon Lee
DSDong In Suh
Dong In Suh
YSYoun Ho Shin
Youn Ho Shin
BKByoung-Ju Kim
Byoung-Ju Kim
SHSoo-Jong Hong
Soo-Jong Hong
This paper describes the background, aim, and design of a prospective birth-cohort study in Korea called the COhort for Childhood Origin of Asthma and allergic diseases (COCOA). COCOA objectives are to investigate the individual and interactive effects of genetics, perinatal environment, maternal lifestyle, and psychosocial stress of mother and child on pediatric susceptibility to allergic diseases. The participants in COCOA represents a Korean inner-city population. Recruitment started on 19 November, 2007 and will continue until 31 December, 2015. Recruitment is performed at five medical centers and eight public-health centers for antenatal care located in Seoul. Participating mother-baby pairs are followed from before birth to adolescents. COCOA investigates whether the following five environmental variables contribute causally to the development and natural course of allergic diseases: (1) perinatal indoor factors (i.e. house-dust mite, bacterial endotoxin, tobacco smoking, and particulate matters 2.5 and 10), (2) perinatal outdoor pollutants, (3) maternal prenatal psychosocial stress and the child’s neurodevelopment, (4) perinatal nutrition, and (5) perinatal microbiome. Cord blood and blood samples from the child are used to assess whether the child’s genes and epigenetic changes influence allergic-disease susceptibility. Thus, COCOA aims to investigate the contributions of genetics, epigenetics, and various environmental factors in early life to allergic-disease susceptibility in later life. How these variables interact to shape allergic-disease susceptibility is also a key aim. The COCOA data collection schedule includes 11 routine standardized follow-up assessments of all children at 6 months and every year until 10 years of age, regardless of allergic-disease development. The mothers will complete multiple questionnaires to assess the baseline characteristics, the child’s exposure to environmental factors, maternal pre- and post-natal psychological stress, and the child’s neurodevelopment, nutritional status, and development of allergic and respiratory illnesses. The child’s microbiome, genes, epigenetics, plasma cytokine levels, and neuropsychological status, the microbiome of the residence, and the levels of indoor and outdoor pollutants are measured by standard procedures. The COCOA study will improve our understanding of how individual genetic or environmental risk factors influence susceptibility to allergic disease and how these variables interact to shape the phenotype of allergic diseases.

8 January 2022 in Journal of Clinical Medicine
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YCYun Jung Choi
Yun Jung Choi
ECEun Hee Chung
Eun Hee Chung
ELEun Lee
Eun Lee
CKChul-Hong Kim
Chul-Hong Kim
YLYong Ju Lee
Yong Ju Lee
DSDong In Suh
Dong In Suh
Mycoplasma pneumoniae is a major causative pathogen of community-acquired pneumonia in children, and the treatment of choice is macrolides. There is an increasing trend in reports of refractory clinical responses despite macrolide treatment due to the emergence of macrolide-resistant M. pneumoniae. Early discrimination of macrolide-refractory M. pneumoniae pneumonia (MrMP) from macrolide-sensitive M. pneumoniae pneumonia (MSMP) is vital; however, testing for macrolide susceptibility at the time of admission is not feasible. This study aimed to identify the characteristics of MrMP in Korean children, in comparison with those of MSMP. In this multicenter study, board-certified pediatric pulmonologists at 22 tertiary hospitals reviewed the medical records from 2010 to 2015 of 5294 children who were hospitalized with M. pneumoniae pneumonia and administered macrolides as the initial treatment. One-way analysis of variance and the Kruskal-Wallis test were used to compare differences between groups. Of 5294 patients (mean age, 5.6 years) included in this analysis, 240 (4.5%), 925 (17.5%), and 4129 (78.0%) had MrMP, macrolide-less effective M. pneumoniae pneumonia, and MSMP, respectively. Compared with the MSMP group, the MrMP group had a longer fever duration, overall (13.0 days) and after macrolide use (8.0 days). A higher proportion of MrMP patients had respiratory distress, pleural effusion, and lobar pneumonia. The mean aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and C-reactive protein levels were the highest in the MrMP group, along with higher incidences of extrapulmonary manifestations and atelectasis (during and post infection). Pre-existing conditions were present in 17.4% (n = 725/4159) of patients, with asthma being the most common (n = 334/4811, 6.9%). This study verified that MrMP patients show more severe initial radiographic findings and clinical courses than MSMP patients. MrMP should be promptly managed by agents other than macrolides.

1 January 2018 in Allergy, Asthma & Immunology Research
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MKMi-Ae Kim
Mi-Ae Kim
DKDong-Kyu Kim
Dong-Kyu Kim
HYHyeon-Jong Yang
Hyeon-Jong Yang
YYYoung Yoo
Young Yoo
YAYoungmin Ahn
Youngmin Ahn
CIClinical Immunology
Clinical Immunology
Kim MA, et al. Allergy Asthma Immunol Res. 2018 Nov;10(6):648-661. https://doi.org/10.4168/aair.2018.10.6.648

Verified
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DCDong-Il Chun
Dong-Il Chun
SKSangyoung Kim
Sangyoung Kim
JKJahyung Kim
Jahyung Kim
HYHyeon-Jong Yang
Hyeon-Jong Yang
JKJae Heon Kim
Jae Heon Kim
SWSung Hun Won
Sung Hun Won
Information about the epidemiology of diabetic foot ulcer (DFU) with peripheral arterial disease (PAD) is likely to be crucial for predicting future disease progression and establishing a health care budget. We investigated the incidence and prevalence of DFU and PAD in Korea. In addition, we examined costs of treatments for DFU and PAD. This study was conducted using data from Health Insurance Review and Assessment Service from 1 January 2011 to 31 December 2016. The incidence of DFU with PAD was 0.58% in 2012 and 0.49% in 2016. The prevalence of DFU with PAD was 1.7% in 2011 to 1.8% in 2016. The annual amputation rate of DFU with PAD was 0.95% in 2012 and 1.10% in 2016. Major amputation was decreased, while minor amputation was increased. The direct cost of each group was increased, especially the limb saving group. which was increased from 296 million dollars in 2011 to 441 million dollars in 2016. The overall incidence of DFU with PAD was about 0.5% of total population in Korea, from 2012 to 2016. Furthermore, costs for treatments of diabetic foot ulcer are increasing, especially those for the limb saving group.