Background: An international reference measurement laboratory network for creatinine (Cr) is lacking; therefore, Korea developed an independent evaluation and certification system. The in vitro diagnostics (IVD) certification program, launched in 2017, formed part of a broader Cr standardization initiative intended to enhance accuracy at the manufacturing stage. Methods: The program was designed to evaluate analytical systems, including all reagent lots, calibrators, and instrument models, twice annually. Bias, imprecision, total error (TE), and linearity were evaluated based on established acceptance criteria. A post-certification process allows submission for a second challenge and validation of corrective actions. Results: Between 2017 and 2023, 489 analytical systems were evaluated. Average acceptance rates for bias, imprecision, TE, and linearity were 70.8%, 95.9%, 87.7%, and 87.8%, respectively. The lowest acceptance rate for bias evaluation was 8.7% for the kinetic Jaffe method without compensation in 2018. Over the 7-year period, the mean absolute percentage bias (absBias%), coefficient of variation (CV), and TE were 4.62%, 1.37%,and 7.29%, respectively. The highest absBias% (7.94%) was observed in the 0.0 ≤ Cr < 1.0target value range. Since 2019, a consistent reduction in absBias% has been observed. Conclusions This program is a pioneering response to the absence of a global certification program for Cr assays. It offers significant advantages, including comprehensive evaluations, fee-free participation, and a robust post-certification process. Continuous participation and improvement efforts by manufacturers have contributed to enhanced accuracy in Cr assays.

Purpose: This study aimed to describe adult living donor liver transplantation (LDLT) for acute liver failure and evaluate its clinical significance by comparing its surgical and survival outcomes with those of deceased donor liver transplantation (DDLT). Methods: We retrospectively reviewed the medical records of 267 consecutive patients (161 LDLT recipients and 106 DDLT recipients) aged 18 years or older who underwent liver transplantation between January 2006 and December 2020. Results: The mean periods from hepatic encephalopathy to liver transplantation were 5.85 days and 8.35 days for LDLT and DDLT, respectively (P = 0.091). Among these patients, 121 (45.3%) had grade III or IV hepatic encephalopathy (living, 34.8% vs. deceased, 61.3%; P < 0.001), and 38 (14.2%) had brain edema (living, 16.1% vs. deceased, 11.3%; P = 0.269) before liver transplantation. There were no significant differences in in-hospital mortality (living, 11.8% vs. deceased, 15.1%; P = 0.435), 10-year overall survival (living, 90.8% vs. deceased, 84.0%; P = 0.096), and graft survival (living, 83.5% vs. deceased, 71.3%;P = 0.051). However, postoperatively, the mean intensive care unit stay was shorter in the LDLT group (5.0 days vs. 9.5 days, P < 0.001). In-hospital mortality was associated with vasopressor use (odds ratio [OR], 3.40; 95% confidence interval [CI], 1.45–7.96; P = 0.005) and brain edema (OR, 2.75; 95% CI, 1.16–6.52; P = 0.022) of recipient at the time of transplantation. However, LDLT (OR, 1.26; 95% CI, 0.59–2.66; P = 0.553) was not independently associated with in-hospital mortality. Conclusion LDLT is feasible for acute liver failure when organs from deceased donors are not available.

Background: Recent studies have reported the burden of attention deficit hyperactivity disorder [ADHD], autism spectrum disorder [ASD], and depressive disorder. Also, there is mounting evidence on the effects of environmental factors, such as ambient air pollution, on these disorders among children and adolescents. However, few studies have evaluated the burden of mental disorders attributable to air pollution exposure in children and adolescents. Methods: We estimated the risk ratios of major mental disorders (ADHD, ASD, and depressive disorder) associated with air pollutants among children and adolescents using time-series data (2011–2019) obtained from a nationwide air pollution monitoring network and healthcare utilization claims data in the Republic of Korea. Based on the estimated risk ratios, we determined the population attributable fraction (PAF) and calculated the medical costs of major mental disorders attributable to air pollution. Results: A total of 33,598 patients were diagnosed with major mental disorders during 9 years. The PAFs for all the major mental disorders were estimated at 6.9% (particulate matter < 10 μm [PM10 ]), 3.7% (PM2.5 ), and 2.2% (sulfur dioxide [SO2 ]). The PAF of PM10 was highest for depressive disorder (9.2%), followed by ASD (8.4%) and ADHD (5.2%). The direct medical costs of all major mental disorders attributable to PM10 and SO2 decreased during the study period. Conclusion This study assessed the burden of major mental disorders attributable to air pollution exposure in children and adolescents. We found that PM10, PM2.5 , and SO2 attributed 7%, 4%, and 2% respectively, to the risk of major mental disorders among children and adolescents.

While the Korean Triage and Acuity Scale (KTAS) was introduced in 2016 as a tool to identify patients at risk of catastrophic events, including death in the ED, the triage system for the pre-hospital stage still lacks evidence. The pre-hospital stage is characterized by time-sensitive and complex scenarios, where rapid and accurate decision-making is paramount to optimize patient outcomes. Despite the vital role of pre-hospital care providers, the invalidated and subjective current triage system consisting of 4-stages is still used at the pre-hospital stage, and hence, it needs to be modified to be more objective, standardized, and reliable. To improve the Korean emergency medical system, the pre-hospital KTAS (Pre-KTAS) was developed in 2020, and then two pilot projects were conducted in 2022 and 2023. This paper not only reveals the results of the first and second pilot projects for Pre-KTAS but also highlights the potential benefits of using this newly developed triage tool in the pre-hospital setting. Furthermore, this paper suggests ways to improve the emergency medical system (EMS) in Korea by improving patient safety, resource allocation, and overall emergency response efficiency.

Objective: The emergency department (ED) serves as the initial point of contact for many sepsis patients, but crowding can affect the timely delivery of essential interventions, such as antibiotics. This paper explores the relationship between antibiotics administration and ED crowding in the context of sepsis management. Methods: This single-center study at a tertiary care hospital included adult patients aged 18 and above who visited the emergency department from January 2018 to December 2022. Patients showing signs of septic shock upon arrival were selected as the study population. This study examined factors such as emergency department occupancy, antibiotic administration time, and their correlation with timely antibiotic treatment. Results: This study of 839 adult patients with septic shock found a weak correlation (P=0.107) between the time to antibiotic administration and department occupancy. Delayed antibiotic administration was observed when the occupancy exceeded 100%. On the other hand, there was no significant correlation between antibiotic administration within one hour and department occupancy. Conclusion Various factors, such as ED bed occupancy, medical staffing, resource allocation, and patient acuity, must be considered when comprehensively evaluating the impact of ED overcrowding on treating septic shock and other conditions.

Background: New creatinine-based estimated glomerular filtration rate (eGFR) equations, including the 2021 Chronic Kidney Disease Epidemiology Collaboration (2021 CKD-EPI) and European Kidney Function Consortium (EKFC) equations, have been introduced recently. We assessed the performance of the 2021 CKD-EPI and EKFC equations in the Korean population. Methods: We analyzed 1,654 Korean patients aged ≥18 years who underwent chromium-51-ethylenediamine tetraacetic acid GFR measurements (mGFR). Bias (eGFR–mGFR), root mean square error (RMSE), and proportion of eGFR within 30% of mGFR (P30) of the 2009 CKD-EPI, 2021 CKD-EPI, and EFKC equations were compared. The concordance rate between eGFR and mGFR categories was evaluated. Both eGFR and mGFR categories were classified into six groups: ≥90, 89–60, 59–45, 44–30, 29–15, and <15 mL/min/1.73 m2. Results: The median bias (mL/min/1.73 m2) was 1.8 for the 2009 CKD-EPI equation, 4.8 for the 2021 CKD-EPI equation, and –0.3 for the EKFC equation. The P30 and RMSE were 78.2% and 17.0 for the 2009 CKD-EPI equation, 75.6% and 17.4 for the 2021 CKD-EPI equation, and 80.0% and 16.7 for the EKFC equation, respectively. The overall GFR category concordance rate between eGFR and mGFR was 63.4% for the 2009 CKD-EPI equation, 60.5% for the 2021 CKD-EPI equation, and 61.0% for the EKFC equation. Conclusions Among the three eGFR equations, the EKFC equation had the smallest bias and highest P30 in Koreans. The 2009 CKD-EPI equation had a lower bias than the 2021 CKD-EPI equation.

Background: To ensure valid results of big data research in the medical field, the input laboratory results need to be of high quality. We aimed to establish a strategy for evaluating the quality of laboratory results suitable for big data research. Methods: We used Korean Association of External Quality Assessment Service (KEQAS) data to retrospectively review multicenter data. Seven measurands were analyzed using commutable materials: HbA1c, creatinine (Cr), total cholesterol (TC), triglyceride (TG), alpha-fetoprotein (AFP), prostate-specific antigen (PSA), and cardiac troponin I (cTnI). These were classified into three groups based on their standardization or harmonization status. HbA1c, Cr, TC, TG, and AFP were analyzed with respect to peer group values. PSA and cTnI were analyzed in separate peer groups according to the calibrator type and manufacturer, respectively. The acceptance rate and absolute percentage bias at the medical decision level were calculated based on biological variation criteria. Results: The acceptance rate (22.5%–100%) varied greatly among the test items, and the mean percentage biases were 0.6%–5.6%, 1.0%–9.6%, and 1.6%–11.3% for all items that satisfied optimum, desirable, and minimum criteria, respectively. Conclusions The acceptance rate of participants and their external quality assessment (EQA) results exhibited statistically significant differences according to the quality grade for each criterion. Even when they passed the EQA standards, the test results did not guarantee the quality requirements for big data. We suggest that the KEQAS classification can serve as a guide for building big data.

Objective: To investigate the relationship between reduced glutathione (GSH), a key molecule of the antioxidant defense system in the blood, and glutathione reductase (GR), which reduces oxidized glutathione (glutathione disulfide [GSSG]) to GSH and maintains the redox balance, with the prevalence of Alzheimer’s dementia and cognitive decline. Methods: In all, 20 participants with Alzheimer’s dementia who completed the third follow-up clinical evaluation over 6 years were selected, and 20 participants with normal cognition were selected after age and sex matching. The GSH and GR concentrations were the independent variables. Clinical diagnosis and neurocognitive test scores were the dependent variables indicating cognitive status. Results: The higher the level of GR, the greater the possibility of having normal cognition than of developing Alzheimer’s dementia. Additionally, the higher the level of GR, the higher the neurocognitive test scores. However, this association was not significant for GSH. After 6 years, the conversion rate from normal cognition to cognitive impairment was significantly higher in the lower 50th percentile of the GR group than in the upper 50th percentile. Conclusion The higher the GR, the lower the prevalence of Alzheimer’s dementia and incidence of cognitive impairment and the higher the cognitive test scores. Therefore, GR is a potential protective biomarker against Alzheimer’s dementia and cognitive decline.