Objective: To establish local diagnostic reference levels (DRLs) for pediatric neck CT based on age, weight, and water-equivalent diameter (WED) across multiple university hospitals in South Korea. Materials and Methods: This retrospective study analyzed pediatric neck CT examinations from nine university hospitals, involving patients aged 0–18 years. Data were categorized by age, weight, and WED, and radiation dose metrics, including volume CT dose index (CTDIvol) and dose length product, were recorded. Data retrieval and analysis were conducted using a commercially available dose-management system (Radimetrics, Bayer Healthcare). Local DRLs were established following the International Commission on Radiological Protection guidelines, using the 75th percentile as the reference value. Results: A total of 1159 CT examinations were analyzed, including 169 scans from Institution 1, 132 from Institution 2, 126 from Institution 3, 129 from Institution 4, 128 from Institution 5, 105 from Institution 6, 162 from Institution 7, 127 from Institution 8, and 81 from Institution 9. Radiation dose metrics increased with age, weight, and WED, showing significant variability both within and across institutions. For patients weighing less than 10 kg, the DRL for CTDIvol was 5.2 mGy. In the 10–19 kg group, the DRL was 5.8 mGy; in the 20–39 kg group, 7.6 mGy; in the 40–59 kg group, 11.0 mGy; and for patients weighing 60 kg or more, 16.2 mGy. DRLs for CTDIvol by age groups were as follows: 5.3 mGy for infants under 1 year, 5.7 mGy for children aged 1–4 years, 7.6 mGy for ages 5–9 years, 11.2 mGy for ages 10–14 years, and 15.6 mGy for patients 15 years or older. Conclusion Local DRLs for pediatric neck CT were established based on age, weight, and WED across nine university hospitals in South Korea.

Objectives: We analyzed the demographic and clinical characteristics of patients diagnosedwith coronavirus disease 2019 (COVID-19), focusing specifically on severe/critical cases, andassessed the trends and rates of severity and fatality among these patients in the Republic of Korea. Methods: Clinical data on patients with COVID-19 from January 20, 2020 to August 30, 2023were collected from the Korea Disease Control and Prevention Agency’s database. We identified patients who progressed to severe/critical conditions and analyzed their demographic and clinical profiles. Severity and fatality rates were calculated and compared annually to track thedisease progression over time. Results: During the surveillance period, 34,572,554 COVID-19 cases were confirmed, among whom 38,112 (0.11%) progressed to severe/critical conditions. Most severe/critical cases occurred in individuals aged ≥60 years, with a notable increase in patients aged ≥80 years from 2022.The overall severity rate was 0.19%, with a fatality rate of 0.10%. However, the severity of cases gradually diminished during the study period. In 2022, the severity and fatality rates decreased to 0.14% and 0.09%, respectively. In 2023, while the severity rate remained stable at 0.15%, thefatality rate further decreased to 0.06%. Notably, throughout the study period, individuals aged ≥80 years had a significantly higher severity rate (2.44%), with a fatality rate of 1.75%. Conclusion These findings underscore the importance of prioritizing protection and management strategies for older adults and high-risk groups to mitigate the impact ofCOVID-19. Continued surveillance and analysis are essential to effectively control COVID-19 and minimize its burden on public health.

Objective: Adult attachment style is linked to how an individual responds to threats or stress and is known to be related to the onset of psychiatric symptoms such as depression. However, as the current assessment of attachment type mainly relies on self-report questionnaires and can be prone to bias, there is a need to incorporate physiological factors along with psychological symptoms and history in this process. We aimed to predict the measurement of two important types of adult attachment with heart rate variability (HRV), early life stress experience, and subjective psychiatric symptoms. Methods: Five hundred eighty-two subjects with depressive disorder were recruited retrospectively from January 2015 to June 2021. The experience of early life stress and psychiatric symptoms were collected, and HRV measures were obtained as input for an ensembled Voting Regressor model of machine learning-based regression models, including linear regression, ElasticNet, Support Vector Machine (SVM), Random Forest, and Extreme Gradient Boosting (XGBoost). Results: Model performances evaluated with R-squared score averaged across 30 seeds were 0.377 and 0.188 for anxious- and avoidant-attachment, respectively. Mean absolute error averaged to 13.251 and 12.083, respectively. Shapley value importance analysis indicated that for both attachment types, the most important feature was the trait-anxiety, followed by emotional abuse, state-anxiety or self-reported depressive symptoms, and fear or helplessness felt in the moment of an early life stressor. Conclusion Our results provide the evidence base that may be utilized in clinical settings to predict the degree of attachment type using bio-psychological factors.

Background: Understanding disparities in severe coronavirus disease 2019 (COVID-19) outcomes between people with disabilities (PwD) and people without disabilities (PwoD) is crucial, particularly when considering the heterogeneity within PwD and age differences.This study aimed to compare severe COVID-19 outcomes including deaths between PwD and PwoD with analyses stratified by age group and further examined by disability type. Methods: This retrospective, population-based cohort study used linked data from national COVID-19 cases and health insurance for individuals aged ≥ 19 years with COVID-19 from January 2020 to October 2022 in the Republic of Korea. Severe outcomes included severe cases and deaths, with logistic regression analysis of the risk disparities between PwD and PwoD based on age group and disability types. The subgroup analysis considered epidemic periods, accounting for the severe acute respiratory syndrome coronavirus 2 variant circulation. Results: The risk of severe COVID-19 outcomes and deaths among PwD varied by age and disability type. While severe outcomes were most prevalent in the older age groups for both PwD and PwoD, younger PwD faced a markedly higher risk—up to eightfold—compared to PwoD. The risk of disability status was greater than that of comorbidities in the 19–39 age group. Among disability types, individuals with internal organs-related and intellectual disabilities showed higher risk disparities with PwoD in severe outcomes than other types of disabilities. Throughout the pandemic, the disparity in death risk remained similar, with a slight increase in disparity during the omicron period for all severe outcomes in the age groups 19–39 and 40–64 years. Conclusion Prioritizing younger PwD, along with older age groups and people with comorbidities, is crucial in addressing public health crises. Risk-based prioritization is important to reduce overall risk. This includes prioritizing people with nternal organs-related and intellectural disabilities, who face higher health risks among PwD during a pandemic when resources are limited and time is of the essence.

Background: The accuracy of Logical Observation Identifiers Names and Codes (LOINC) mappings is reportedly low, and the LOINC codes used for research purposes in Korea have not been validated for accuracy or usability. Our study aimed to evaluate the discrepancies and similarities in interoperability using existing LOINC mappings in actual patient care settings. Methods: We collected data on local test codes and their corresponding LOINC mappings from seven university hospitals. Our analysis focused on laboratory tests that are frequently requested, excluding clinical microbiology and molecular tests. Codes from nationwide proficiency tests served as intermediary benchmarks for comparison. A research team, comprising clinical pathologists and terminology experts, utilized the LOINC manual to reach a consensus on determining the most suitable LOINC codes. Results: A total of 235 LOINC codes were designated as optimal codes for 162 frequent tests.Among these, 51 test items, including 34 urine tests, required multiple optimal LOINC codes, primarily due to unnoted properties such as whether the test was quantitative or qualitative, or differences in measurement units. We analyzed 962 LOINC codes linked to 162 tests across seven institutions, discovering that 792 (82.3%) of these codes were consistent. Inconsistencies were most common in the analyte component (38 inconsistencies, 33.3%), followed by the method (33 inconsistencies, 28.9%), and properties (13 inconsistencies, 11.4%). Conclusion This study reveals a significant inconsistency rate of over 15% in LOINC mappings utilized for research purposes in university hospitals, underlining the necessity for expert verification to enhance interoperability in real patient care.

Background: Understanding disparities in severe coronavirus disease 2019 (COVID-19) outcomes between people with disabilities (PwD) and people without disabilities (PwoD) is crucial, particularly when considering the heterogeneity within PwD and age differences.This study aimed to compare severe COVID-19 outcomes including deaths between PwD and PwoD with analyses stratified by age group and further examined by disability type. Methods: This retrospective, population-based cohort study used linked data from national COVID-19 cases and health insurance for individuals aged ≥ 19 years with COVID-19 from January 2020 to October 2022 in the Republic of Korea. Severe outcomes included severe cases and deaths, with logistic regression analysis of the risk disparities between PwD and PwoD based on age group and disability types. The subgroup analysis considered epidemic periods, accounting for the severe acute respiratory syndrome coronavirus 2 variant circulation. Results: The risk of severe COVID-19 outcomes and deaths among PwD varied by age and disability type. While severe outcomes were most prevalent in the older age groups for both PwD and PwoD, younger PwD faced a markedly higher risk—up to eightfold—compared to PwoD. The risk of disability status was greater than that of comorbidities in the 19–39 age group. Among disability types, individuals with internal organs-related and intellectual disabilities showed higher risk disparities with PwoD in severe outcomes than other types of disabilities. Throughout the pandemic, the disparity in death risk remained similar, with a slight increase in disparity during the omicron period for all severe outcomes in the age groups 19–39 and 40–64 years. Conclusion Prioritizing younger PwD, along with older age groups and people with comorbidities, is crucial in addressing public health crises. Risk-based prioritization is important to reduce overall risk. This includes prioritizing people with nternal organs-related and intellectural disabilities, who face higher health risks among PwD during a pandemic when resources are limited and time is of the essence.

Background: The accuracy of Logical Observation Identifiers Names and Codes (LOINC) mappings is reportedly low, and the LOINC codes used for research purposes in Korea have not been validated for accuracy or usability. Our study aimed to evaluate the discrepancies and similarities in interoperability using existing LOINC mappings in actual patient care settings. Methods: We collected data on local test codes and their corresponding LOINC mappings from seven university hospitals. Our analysis focused on laboratory tests that are frequently requested, excluding clinical microbiology and molecular tests. Codes from nationwide proficiency tests served as intermediary benchmarks for comparison. A research team, comprising clinical pathologists and terminology experts, utilized the LOINC manual to reach a consensus on determining the most suitable LOINC codes. Results: A total of 235 LOINC codes were designated as optimal codes for 162 frequent tests.Among these, 51 test items, including 34 urine tests, required multiple optimal LOINC codes, primarily due to unnoted properties such as whether the test was quantitative or qualitative, or differences in measurement units. We analyzed 962 LOINC codes linked to 162 tests across seven institutions, discovering that 792 (82.3%) of these codes were consistent. Inconsistencies were most common in the analyte component (38 inconsistencies, 33.3%), followed by the method (33 inconsistencies, 28.9%), and properties (13 inconsistencies, 11.4%). Conclusion This study reveals a significant inconsistency rate of over 15% in LOINC mappings utilized for research purposes in university hospitals, underlining the necessity for expert verification to enhance interoperability in real patient care.

Purpose: This study evaluated the postoperative quality of life (QoL) after various types of gastrectomy for gastric cancer. Materials and Methods: A multicenter prospective observational study was conducted in Korea using the Korean Quality of Life in Stomach Cancer Patients Study (KOQUSS)-40, a new QoL assessment tool focusing on postgastrectomy syndrome. Overall, 496 patients with gastric cancer were enrolled, and QoL was assessed at 5 time points: preoperatively and at 1, 3, 6, and 12 months after surgery. Results: Distal gastrectomy (DG) and pylorus-preserving gastrectomy (PPG) showed significantly better outcomes than total gastrectomy (TG) and proximal gastrectomy (PG) with regard to total score, indigestion, and dysphagia. DG, PPG, and TG also showed significantly better outcomes than PG in terms of dumping syndrome and worry about cancer. Postoperative QoL did not differ significantly according to anastomosis type in DG, except for Billroth I anastomosis, which achieved better bowel habit change scores than the others. No domains differed significantly when comparing double tract reconstruction and esophagogastrostomy after PG. The total QoL score correlated significantly with postoperative body weight loss (more than 10%) and extent of resection (P<0.05 for both).Reflux as assessed by KOQUSS-40 did not correlate significantly with reflux observed on gastroscopy 1 year postoperatively (P=0.064). Conclusions Our prospective observation using KOQUSS-40 revealed that DG and PPG lead to better QoL than TG and PG. Further study is needed to compare postoperative QoL according to anastomosis type in DG and PG.

Purpose: This study aimed to identify reproducible locations for evaluating masseter muscle function by measuring its thickness using ultrasonography (US). The study focused on comparing two measurement locations: the thickest part of the masseter muscle during ultrasonographic scanning (TMUS) and the most prominent part during clenching (PMC). Methods: Forty healthy adults (20 males and 20 females) participated in the study. US images were obtained from both sides of the masseter muscle under resting and clenching conditions. Measurements were taken at the TMUS and PMC locations, and the clenching-to-resting (C/R) ratio was calculated. Intra- and inter-rater reliability were assessed using intraclass correlation coefficients (ICCs), and the agreement between the two locations was further analyzed using Bland–Altman (BA) plots. Results: The measurements at both TMUS and PMC showed high intra- and inter-rater agreement, with no significant difference in measurements between the two locations.However, the PMC location demonstrated slightly higher ICC values (0.94) compared to TMUS (0.91). The C/R ratio for PMC showed higher consistency (0.89) compared to TMUS (0.65). BA plots indicated that the agreement between TMUS and PMC was slightly better during clenching than at rest, with smaller mean differences in clenching (–0.06 mm) than resting (–0.13 mm). Additionally, the number of measurements outside the upper and lower limits was lower during clenching (10) than at rest (13). Conclusions Both TMUS and PMC locations demonstrated reliable measurements, but the PMC location showed slightly better consistency across different muscle states. The findings suggest that PMC provides a more reproducible and standardized approach for masseter muscle assessment, making it a better choice for both clinical practice and research in evaluating masticatory function.

Background: Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making. Methods: This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes. Conclusion This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.