Purpose: There are limited data on the epidemiological and clinical characteristics and outcomes in Korean patients with laboratory-confirmed coronavirus disease 2019 (COVID-19). We aimed to describe the epidemiological and clinical characteristics and outcomes of patients with COVID-19 using the Korean nationwide multicenter database. Methods: In this nationwide multicenter study, we included all confirmed patients of COVID-19 in South Korea from February 1 to April 30, 2020. Subjects were classified into 3 age groups: those at younger than 10 years (children), 10 to 20 years (adolescents), and 20 years or more (adults). Cases were confirmed by laboratory testing using real-time reverse transcriptase-polymerase chain reaction assay and analyzed for epidemiological and clinical features and outcomes. Patents were followed up until April 30, 2020. Results: Of 5,628 patients with COVID-19 (2,320 males [41.2%] and 3,308 females [58.8%]), there were 66 children (1.2%), 206 adolescents (3.7%), and 5,356 adults (95.2%). The common comorbidities were hypertension (1,201, 21.3%), diabetes (691, 12.3%), dementia (224, 4.0%), chronic heart disease (179, 3.2%), cancer (145, 2.6%), and asthma (128, 2.3%). The common presenting symptoms were cough (2,341, 41.6%), sputum (1,619, 28.8%), fever (1,305, 23.2%), headache (967, 17.2%), myalgia (926, 16.5%), and pharyngodynia (881, 15.7%). One hundred sixty-five patients (2.1%) were confirmed as having moderate or severe COVID-19 and 118 (2.1%) as having severe COVID-19. Conclusion Our descriptive study provides the epidemiological and clinical characteristics and outcomes of patients with laboratory-confirmed COVID-19 in South Korea.

OBJECTIVES: This study investigated recent trends in the prevalence of obesity among Korean adolescents and explored socioeconomic disparities in obesity. METHODS: This study used annual self-reported data on height, weight, and socioeconomic information from the Korea Youth Risk Behavior Web-based Survey from 2006 to 2020. With a 95.8% response rate, the sample consisted of 818,210 adolescents. Obesity prevalence was calculated according to 4 socioeconomic indicators (household income, father’s educational attainment, mother’s educational attainment, and urbanicity). Socioeconomic inequality was quantified using the relative index of inequality (RII). RESULTS: The overall prevalence of obesity increased, doubling from 5.9% in 2006 to 11.7% in 2020. Boys and high school students showed a higher prevalence. The RIIs in household income and parental educational attainments significantly increased with time, indicating a growing inequality in obesity. Socioeconomic disadvantages had a greater influence on obesity among girls. The most recent RII values for boys were 1.25 for income, 1.79 for the father’s education, and 1.45 for the mother’s education, whereas the corresponding values for girls were 2.49, 3.17, and 2.62, respectively. CONCLUSIONS These findings highlight growing inequalities in adolescent obesity according to household income and parental educational attainments, especially for girls and middle schoolers.

Despite the improved accuracy and increasing use of prenatal ultrasonography, fetal cholelithiasis is a rarely detected disease, and its natural history and clinical significance are not yet well defined. Many maternal and neonatal risk factors are associated with fetal cholelithiasis. Intrahepatic cholestasis of pregnancy could be a risk factor for fetal cholelithiasis, but no case reports in previous literatures have demonstrated this relationship. We present a case of fetal cholelithiasis in the late third trimester of pregnancy that was related to intrahepatic cholestasis of pregnancy, along with a brief review of associated literatures.
Cholelithiasis* ; Cholestasis, Intrahepatic* ; Female ; Humans ; Natural History ; Pregnancy Trimester, Third ; Pregnancy* ; Risk Factors ; Ultrasonography ; Ultrasonography, Prenatal

Background/Aims: To date, there is no standard tool to diagnose gastroesophageal reflux disease (GERD). Typically, GERD is a non-erosive reflux disease (NERD) that does not present endoscopic abnormalities. Confocal laser endomicroscopy (CLE) has been shown to be an effective tool to identify and diagnose GERD. We aimed to investigate the cellular and vascular changes in vivo and ex vivo through CLE in patients with GERD. Methods: Patients with refractory GERD who underwent mucosectomy were recruited. The distal esophagus was observed in vivo using CLE. Mucosectomy tissue was stained with acriflavine and CLE image was obtained ex vivo. We compared cellular and vascular changes in CLE between erosive reflux disease (ERD), NERD, and a control group. Results: Eleven patients who underwent anti-reflux mucosectomy and five control patients were enrolled in the study. Patients with ERD and NERD presented greater dilated intercellular space than patients in the control group on CLE image. The diameter, number, and cross-sectional area of the intra-papillary capillary loops (IPCLs) were significantly larger in the ERD group than in the NERD group. The irregular shape of the IPCLs were observed in both patients with ERD and NERD. Conclusions The irregular shape of the IPCLs were significantly correlated with a positive diagnosis of GERD. CLE may diagnose NERD with high sensitivity and accuracy.

Background/Aims: Integrated relaxation pressure (IRP) is a critical diagnostic criterion to define achalasia. However, there are some cases with typical symptoms and signs of achalasia but with normal IRP. The aim of this study is to evaluate the clinical characteristics of patients with achalasia with normal IRP and outcomes after peroral endoscopic myotomy (POEM). Methods: Patients with achalasia were collected in whom POEM was performed from November 2014 to April 2018 at CHA Bundang Medical Center. Achalasia with normal IRP was defined by findings compatible to achalasia in Eckardt score, endoscopy with endoscopic ultrasound, high-resolution manometry, impedance planimetry (EndoFlip), and timed esophagogram. Results: POEM was performed in 89 patients with achalasia; among them, 24 (27%) patients were diagnosed with achalasia with normal IRP. Patients with achalasia with normal IRP were older, had longer duration of symptom, and had a more tortuous esophagus. In EndoFlip, the distensibility index and cross-sectional area were higher in patients with normal IRP. Therapeutic outcomes showed no statistically significant differences. On correlation analysis, IRP had negative correlations with age, disease duration, and distensibility index. Conclusions Patients with achalasia of normal IRP value were older and had longer disease duration and higher distensibility index and crosssectional area than patients with achalasia with abnormal relaxation of lower esophageal sphincter. Therapeutic outcomes were not different between the 2 groups.

PURPOSE: Circulating patterns of predominant respiratory syncytial virus (RSV) genotypes in the community may be helpful in understanding molecular epidemiology and predicting future outbreaks of the RSV genotype. We investigated the association of genetic variations in RSV with acute severe bronchiolitis in infants. METHODS: We reviewed medical records of infants younger than 1 year of age hospitalized due to acute bronchiolitis between November 2016 and February 2017. Subjects were classified as severe or mild based on the use of mechanical or noninvasive ventilation. The associations between severity of the disease, sex, age at admission, oxygen saturation at admission and laboratory test results were analyzed. RSV sequence analysis was performed in the severe group. RESULTS: Among 114 infants, 80 underwent respiratory viral polymerase chain reaction using nasopharyngeal swab; of these, 53 (66.3%) showed positive for RSV. Of the 53 RSV-positive samples, 9 were categorized as the severe group and 44 were categorized as the mild group. Male sex, young age, longer duration of admission, minimum SaO2 at admission and bronchiolitis severity score were significantly correlated with disease severity in the severe group than in the mild group (all variables, P < 0.001). Phylogenetic and sequence analysis in the severe group revealed 8 RSV-A, ON1 genotype and 1 RSV-B, BA4 genotype. CONCLUSION: Phylogenetic types of RSV in subjects of the severe group were RSV-A, ON1 genotype or RSV-B, BA4 genotype which were prevalent in the Korean community at the same time. Our study showed that disease severity was not significantly associated with RSV genotypic evolution or antigenic drift in Korea during winter season 2016–17.
Bronchiolitis* ; Disease Outbreaks ; Genetic Variation* ; Genotype ; Humans ; Infant* ; Korea* ; Male ; Medical Records ; Molecular Epidemiology ; Noninvasive Ventilation ; Oxygen ; Polymerase Chain Reaction ; Respiratory Syncytial Viruses* ; Seasons* ; Sequence Analysis

Background: Many studies have evaluated the prevalence of different reasons for retraction in samples of retraction notices. We aimed to perform a systematic review of such empirical studies of retraction causes. Methods: The PubMed/MEDLINE database and the Embase database were searched in June 2023. Eligible studies were those containing sufficient data on the reasons for retraction across samples of examined retracted notices. Results: A 11,181 potentially eligible items were identified, and 43 studies of retractions were included in this systematic review. Studies limited to retraction notices of a specific subspecialty or country, journal/publication type are emerging since 2015. We noticed that the reasons for retraction are becoming more specific and more diverse. In a meta-analysis of 17 studies focused on different subspecialties, misconduct was responsible for 60% (95% confidence interval [CI], 53–67%) of all retractions while error and publication issues contributed to 17% (95% CI, 12–22%) and 9% (95% CI, 6–13%), respectively. The end year of the retraction period in all included studies and the proportion of misconduct presented a weak positive association (coefficient = 1.3% per year, P = 0.002). Conclusion Misconduct seems to be the most frequently recorded reason for retraction across empirical analyses of retraction notices, but other reasons are not negligible. Greater specificity of causes and standardization is needed in retraction notices.

Epidemiological studies have shown that exposure to tobacco smoke causing irritation and inflammation in the airways tends to reduce serum periostin concentrations in adults. We now investigate prospective cross-sectional study on 135 Korean students aged 7 years in the first grade who were participating in the Seongnam Atopy Project for Children's Happiness 2016 (SAP2016) cohort. To the best of our knowledge, this is the first study to show significant inverse correlations between serum periostin concentration and exposure to xylene and formaldehyde in children. Our findings suggested the need for caution in using the serum periostin level as a marker for allergic diseases, since exposure to volatile organic compounds and formaldehyde may confound the interpretation of these results.
Adult ; Child* ; Cohort Studies ; Cross-Sectional Studies ; Epidemiologic Studies ; Formaldehyde* ; Gyeonggi-do ; Happiness ; Humans ; Inflammation ; Prospective Studies ; Smoke ; Tobacco ; Volatile Organic Compounds* ; Xylenes

PURPOSE: Children with sensitization to aeroallergens have decreased lung function and nasal patency. Our purpose was to determine the association of sensitization to different aeroallergens with airway function and nasal patency. METHODS: Four hundred and eighty-six randomly selected 11 year-old children who lived in Seongnam City were examined. Serum specific immunoglobulin E (IgE) levels against 6 common allergens (Dermatophagoidesfarinae, birch, cat, dog, Japanese hop and Alternaria), impulse oscillometry (IOS) results for the evaluation of airway dysfunction, and acoustic rhinometry for the determination of nasal airway patency were obtained. RESULTS: IOS indicated that children sensitized to Alternaria (n = 38, 7.8%) and dog dander (n = 69, 14.2%) had decreased lung function, based on resistance at 10 Hz (Rrs10; aβ = 0.0072; 95% CI, 0.017, 0.127; P = 0.010) and 1 Hz (Rrs1; aβ = 0.038; 95% CI, 0.001, 0.074; P = 0.042). Children sensitized to D. farinae (n = 281, 57.8%) had decreased post-decongestant nasal volume at 0 to 5 cm (aβ = −0.605; 95% CI, −1.005, −0.205; P = 0.003), but normal IOS results at all measured frequencies (P > 0.05). Increased serum eosinophil level was associated with Rrs1 (P = 0.007) and Rrs2 (P = 0.018) and post-decongestant nasal volume at 0 to 5 cm (aβ = −0.885; 95% CI, −1.331, −0.439; P < 0.001). CONCLUSIONS: Sensitivity to specific aeroallergens, serum eosinophil count and total IgE level had different associations with upper and lower airway dysfunction in urban children.
Allergens ; Alternaria ; Animals ; Asian Continental Ancestry Group ; Betula ; Cats ; Child ; Dander ; Dogs ; Eosinophils ; Gyeonggi-do ; Humans ; Immunoglobulin E ; Immunoglobulins ; Jupiter ; Lung ; Oscillometry ; Respiratory Function Tests ; Rhinometry, Acoustic

Background: Evidence for the association between underlying non-alcoholic fatty liver disease (NAFLD), the risk of testing severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) positive, and the clinical consequences of coronavirus disease 2019 (COVID-19) is controversial and scarce. We aimed to investigate the association between the presence of NAFLD and the risk of SARS-CoV-2 infectivity and COVID-19-related outcomes. Methods: We used the population-based, nationwide cohort in South Korea linked with the general health examination records between January 1, 2018 and July 30, 2020. Data for 212,768 adults older than 20 years who underwent SARS-CoV-2 testing from January 1 to May 30, 2020, were obtained. The presence of NAFLDs was defined using three definitions, namely hepatic steatosis index (HSI), fatty liver index (FLI), and claims-based definition. The outcomes were SARS-CoV-2 test positive, COVID-19 severe illness, and related death. Results: Among 74,244 adults who completed the general health examination, there were 2,251 (3.0%) who were SARS-CoV-2 positive, 438 (0.6%) with severe COVID-19 illness, and 45 (0.06%) COVID-19-related deaths. After exposure-driven propensity score matching, patients with pre-existing HSI-NAFLD, FLI-NAFLD, or claims-based NAFLD had an 11–23% increased risk of SARS-CoV-2 infection (HSI-NAFLD 95% confidence interval [CI], 1–28%; FLI-NAFLD 95% CI, 2–27%; and claims-based NAFLD 95% CI, 2–31%) and a 35–41% increased risk of severe COVID-19 illness (HSI-NAFLD 95% CI, 8–83%; FLI-NAFLD 95% CI, 5–71%; and claims-based NAFLD 95% CI, 1–92%). These associations are more evident as liver fibrosis advanced (based on the BARD scoring system). Similar patterns were observed in several sensitivity analyses including the full-unmatched cohort. Conclusion Patients with pre-existing NAFLDs have a higher likelihood of testing SARSCoV-2 positive and severe COVID-19 illness; this association was more evident in patients with NAFLD with advanced fibrosis. Our results suggest that extra attention should be given to the management of patients with NAFLD during the COVID-19 pandemic.