1.Acute Heart Failure Across the Ejection Fraction Spectrum: Phenotypes, Management, and Outcomes From Nationwide KorHF III Registry
Huijin LEE ; Eung Ju KIM ; Seong Woo HAN ; Seong-Mi PARK ; Hyung-Seop KIM ; Myung-Chan CHO ; Hyo-Suk AHN ; Mi-Seung SHIN ; Seok-Jae HWANG ; Jin-Ok JEONG ; Dong Heon YANG ; Junho HYUN ; Jin Oh CHOI ; Hae-Young LEE ; Byung-Su YOO ; Seok-Min KANG ; Dong-Ju CHOI ; Hyun-Jai CHO ;
International Journal of Heart Failure 2026;8(1):43-55
Background and Objectives:
Clinical characteristics and outcomes in acute heart failure (AHF) vary by phenotype. We assessed phenotype-specific features, treatment patterns, and outcomes in a nationwide Korean cohort.
Methods:
The Korean Heart Failure III registry prospectively enrolled 7,351 AHF admissions at 47 hospitals. Among 6,777 patients with available left ventricular ejection fraction (EF), phenotypes were defined as heart failure with reduced EF (HFrEF, ≤40%), mildly reduced EF (HFmrEF,41–49%), or preserved EF (HFpEF, ≥50%). The primary endpoint was a 12-month composite of all-cause death or heart transplantation, evaluated from index admission and, among hospital survivors, from discharge. We used inverse probability weighting (multinomial generalized boosted models with stabilized, trimmed weights) and weighted Cox proportional-hazards models to estimate hazard ratios (HRs).
Results:
Phenotype distribution was 58.9% HFrEF, 13.6% HFmrEF, and 27.5% HFpEF. Crude 12-month composite rates from index admission were 13.4% (HFrEF), 12.7% (HFmrEF), and 16.8% (HFpEF). After weighting, from index admission, HFmrEF (HR, 0.892; 95% confidence interval [CI], 0.731–1.088) and HFpEF (HR, 1.101; 95% CI, 0.939–1.291) did not differ from HFrEF; from discharge, HFpEF had modestly higher risk (HR, 1.207; 95% CI, 1.008–1.445) whereas HFmrEF did not (HR, 1.039; 95% CI, 0.844–1.279). Hyponatremia and chronic kidney disease were consistent adverse markers, while angiotensin-converting enzyme inhibitor/ angiotensin II receptor blocker use at discharge was protective.
Conclusions
Across the EF spectrum, phenotypes showed distinct profiles and risk. Postdischarge risk was modestly higher in HFpEF, supporting phenotype-tailored care and systematic discharge optimization in Korean patients with AHF.
2.Considerations of Flow Cytometric Lymphocyte Subset Analysis in Korea Based on a Survey of Current Clinical Laboratory Practice
Mikyoung PARK ; Hyun-Woo CHOI ; Jihyang LIM ; Kyung-Hwa SHIN ; Eun-Jee OH ; Jaewoo SONG ; Kyeong-Hee KIM ; In Hwa JEONG ; Joo-Heon PARK ; Sang-Hyun HWANG ; Eun-Suk KANG
Annals of Laboratory Medicine 2026;46(2):220-225
Flow cytometric lymphocyte subset analysis (FCLSA) is essential for assessing immune status across various diseases and clinical settings. We surveyed current clinical laboratory practices related to FCLSA to establish a baseline reference for future standardization in Korea. Nine university hospitals actively performing FCLSA responded to the 22-question survey, which covered seven categories of laboratory practice. These hospitals used commercial reagent antibody kits from either Beckton Dickinson Biosciences (N = 4) or Beckman Coulter Diagnostics (N = 5). Most hospitals performed daily instrument setup and scheduled maintenance every 2–6 months. Two levels of commercial quality control materials were routinely used each day. Sample and reagent antibody volumes varied across hospitals, even when the same reagent kit was used. Acquired cell counts ranged from 5 × 10 3 to 5 × 10 4 cells, with two hospitals adjusting counts based on the cell type analyzed. Most laboratories reported percentages and general opinions; some additionally reported white blood cell and lymphocyte counts, along with lymphocyte percentages. This is the first comprehensive survey on the clinical laboratory practice of FCLSA in Korea.Standardization of FCLSA should be accelerated to ensure reliable and reproducible results.
3.Clinical Practice Guideline for the Prehospital Stage of Acute Stroke : III. Initial Decision for Primary Treatment in Subarachnoid Hemorrhage
Jae Sang OH ; Jong Min LEE ; Hong Suk AHN ; Jung-Jae KIM ; Kyoung Min JANG ; Gi-Yong YUN ; Jang Hun KIM ; Dongwook SEO ; Hyeong Jin LEE ; Yuna JO ; Jinwoo JEONG ; Kyoung-Chul CHA ; Yong Soo CHO ; Su Jin KIM ; Jongkyu PARK ; Won-Sang CHO ; Hoon KIM ; Young Woo KIM ; Seung Hun SHEEN ; Sang Weon LEE ; Jae Whan LEE ; Tae Gon KIM ; Sung-kon HA ; Sukh Que PARK ; Dae-Won KIM ; Soon Chan KWON
Journal of Korean Neurosurgical Society 2026;69(1):35-50
Subarachnoid hemorrhage (SAH) is a stroke subtype with high mortality and poor functional outcomes. Prompt occlusion of a ruptured aneurysm at an early stage is crucial to prevent rebleeding, which can result in even higher mortality and more severe disabilities. The most critical initial decision in SAH management is the choice of treatment method with surgical clipping or endovascular coiling. We aimed to develop an evidence-based clinical guideline to select the optimal initial treatment in patients with SAH. We developed this guideline based on evidence from systematic reviews and meta-analyses via a de novo process. A systematic literature review was conducted across four databases (MEDLINE, Embase, Cochrane, and KoreaMed) to answer two population, intervention, comparison, outcome questions comparing clipping and coiling. The risk of bias was assessed using ROB 2.0 and the Newcastle-Ottawa Scale. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagrams and meta-analyses were generated for functional outcome and mortality. We included six randomized control trials (RCTs) and 58 observational studies. Meta-analysis of RCTs showed that coiling improved functional outcomes compared to clipping (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.86–0.97). No significant mortality difference was observed in RCTs (OR, 1.38; 95% CI, 0.91–2.09), but non-RCTs favored clipping for reduced mortality (OR, 0.77; 95% CI, 0.69–0.86). However, it is difficult to generalize these findings to all clinical situations, as patients with SAH have a highly variable clinical course. Final treatment decision should be tailored to the individual patient’s status, including aneurysm location, morphology, and the expertise available at the treatment center. Such decisions are best made by specialists such as a board-certified physician and should be explained to the patient and their caregivers, along with the rationale for selecting the most appropriate treatment at the given hospital. Korea has many certified endovascular neurosurgeons, cerebrovascular surgeons, and certified cerebrovascular centers. Proper selection of the most suitable treatment method by certified physicians and centers would greatly benefit patient outcomes and healthcare professionals.
4.Clinical Practice Guideline for the Prehospital Stage in Acute Stroke : I. Use of Emergency Medical Services Assessment Tools
Jae Sang OH ; Dongwook SEO ; Jinwoo JEONG ; Kyoung-Chul CHA ; Yong Soo CHO ; Su Jin KIM ; Jongkyu PARK ; Won-Sang CHO ; Se Won OH ; Jang Hun KIM ; Hyeong Jin LEE ; Hong Suk AHN ; Yuna JO ; Jung-Jae KIM ; Kyoung Min JANG ; Gi-Yong YUN ; Jong Min LEE ; Hoon KIM ; Young Woo KIM ; Tae Gon KIM ; Sung-kon HA ; Sukh Que PARK ; Soon Chan KWON
Journal of Korean Neurosurgical Society 2026;69(1):7-22
Accurate and early identification of stroke and large vessel occlusion (LVO) in emergency settings is essential for improving patient outcomes and ensuring the efficient allocation of medical resources. This clinical practice guideline systematically reviews domestic and international literature and conducts meta-analyses to evaluate the utility and diagnostic accuracy of stroke assessment tools used in prehospital emergency medical services (EMS). We developed a guideline based on evidence from systematic reviews and meta-analyses via a de novo process. A systematic literature review was conducted to evaluate the usefulness of diagnostic EMS assessment tools for diagnosing stroke and LVO. Overall, 70 non-randomized control studies were selected for this study. A meta-analysis was conducted with a subgroup analysis to distinguish between patients with stroke and those with LVO. EMS tools demonstrated high sensitivity but low specificity for diagnosing stroke. In the prehospital setting, using validated EMS stroke assessment tools is recommended for the early identification of stroke and LVO. Upon hospital arrival, stroke specialists should conduct further evaluation and triage to confirm the diagnosis and guide appropriate management. Delays in diagnosing LVO are frequently unacceptable. While experts advocate for the use of EMS assessment tools to facilitate early identification of LVO, these tools alone lack adequate sensitivity. Therefore, further diagnostic evaluations and consultation with stroke specialists upon hospital arrival are recommended.
5.Clinical Practice Guidelines for the Prehospital Stage of Acute Stroke in Korea II : Transport Decisions for Patients with Acute Ischemic Stroke
Jae Sang OH ; Yuna JO ; Jong Min LEE ; Hong Suk AHN ; Jung-Jae KIM ; Kyoung Min JANG ; Gi-Yong YUN ; Jang Hun KIM ; Dongwook SEO ; Hyeong Jin LEE ; Jinwoo JEONG ; Kyoung-Chul CHA ; Yong Soo CHO ; Su Jin KIM ; Jongkyu PARK ; Won-Sang CHO ; Hoon KIM ; Young Woo KIM ; Seung Hun SHEEN ; Sang Weon LEE ; Jae Whan LEE ; Tae Gon KIM ; Sung-kon HA ; Sukh Que PARK ; Soon Chan KWON
Journal of Korean Neurosurgical Society 2026;69(1):23-34
The mothership (MS) model, where patients are directly transferred to a thrombectomy-capable center, and the drip-and-ship (DS) model, where thrombolysis is initiated at the nearest primary stroke center before transfer for thrombectomy, are the primary transport modes for patients with stroke. We aimed to establish guidelines for selecting the appropriate transfer strategy based on emergent large vessel occlusion (LVO). We developed this guideline based on evidence from systematic reviews and meta-analyses via a de novo process. A systematic literature review was conducted across four databases (MEDLINE, Embase, Cochrane, and KoreaMed) to answer three Population, Intervention, Comparison, and Outcome questions comparing MS and DS models. The risk of bias was assessed using the Newcastle-Ottawa Scale. Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagrams and meta-analyses were generated for functional outcomes, mortality, and successful recanalization. Twenty-six non-randomized controlled studies showed that the MS model improved good functional outcomes by approximately 14% compared with the DS model (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.00–1.30). Fifteen studies reported that mortality in the MS and DS models showed no significant differences (OR, 0.97; 95% CI, 0.84–1.11). Twenty-four studies revealed no significant difference in successful recanalization between the MS and DS models (OR, 0.87; 95% CI, 0.68–1.10). The MS model should be considered first to improve the functional outcome of patients with LVO. However, if thrombectomy cannot be performed immediately after thrombolysis, or if a thrombectomy-enabled hospital is not nearby, the DS model should be considered by stroke specialists depending on transportation time and regional factors. We suggest a mixed approach with the DS model based on specific circumstances or regions to ensure the optimum treatment of patients with acute ischemic stroke (AIS). Appropriate transport for patients with LVO improves the prognosis of AIS.
6.Current Status of Flow Cytometric Immunophenotyping of Hematolymphoid Neoplasms in Korea
Mikyoung PARK ; Jihyang LIM ; Ari AHN ; Eun-Jee OH ; Jaewoo SONG ; Kyeong-Hee KIM ; Jin-Yeong HAN ; Hyun-Woo CHOI ; Joo-Heon PARK ; Kyung-Hwa SHIN ; Hyerim KIM ; Miyoung KIM ; Sang-Hyun HWANG ; Hyun-Young KIM ; Duck CHO ; Eun-Suk KANG
Annals of Laboratory Medicine 2024;44(3):222-234
Background:
Flow cytometric immunophenotyping of hematolymphoid neoplasms (FCIHLN) is essential for diagnosis, classification, and minimal residual disease (MRD) monitoring. FCI-HLN is typically performed using in-house protocols, raising the need for standardization. Therefore, we surveyed the current status of FCI-HLN in Korea to obtain fundamental data for quality improvement and standardization.
Methods:
Eight university hospitals actively conducting FCI-HLN participated in our survey.We analyzed responses to a questionnaire that included inquiries regarding test items, reagent antibodies (RAs), fluorophores, sample amounts (SAs), reagent antibody amounts (RAAs), acquisition cell number (ACN), isotype control (IC) usage, positiveegative criteria, and reporting.
Results:
Most hospitals used acute HLN, chronic HLN, plasma cell neoplasm (PCN), and MRD panels. The numbers of RAs were heterogeneous, with a maximum of 32, 26, 12, 14, and 10 antibodies used for acute HLN, chronic HLN, PCN, ALL-MRD, and multiple myeloma-MRD, respectively. The number of fluorophores ranged from 4 to 10. RAs, SAs, RAAs, and ACN were diverse. Most hospitals used a positive criterion of 20%, whereas one used 10% for acute and chronic HLN panels. Five hospitals used ICs for the negative criterion. Positiveegative assignments, percentages, and general opinions were commonly reported. In MRD reporting, the limit of detection and lower limit of quantification were included.
Conclusions
This is the first comprehensive study on the current status of FCI-HLN in Korea, confirming the high heterogeneity and complexity of FCI-HLN practices. Standardization of FCI-HLN is urgently needed. The findings provide a reference for establishing standard FCI-HLN guidelines.
7.Prevalence and Associated Factors of Depression and Anxiety Among Healthcare Workers During the Coronavirus Disease 2019 Pandemic:A Nationwide Study in Korea
Shinwon LEE ; Soyoon HWANG ; Ki Tae KWON ; EunKyung NAM ; Un Sun CHUNG ; Shin-Woo KIM ; Hyun-Ha CHANG ; Yoonjung KIM ; Sohyun BAE ; Ji-Yeon SHIN ; Sang-geun BAE ; Hyun Wook RYOO ; Juhwan JEONG ; NamHee OH ; So Hee LEE ; Yeonjae KIM ; Chang Kyung KANG ; Hye Yoon PARK ; Jiho PARK ; Se Yoon PARK ; Bongyoung KIM ; Hae Suk CHEONG ; Ji Woong SON ; Su Jin LIM ; Seongcheol YUN ; Won Sup OH ; Kyung-Hwa PARK ; Ju-Yeon LEE ; Sang Taek HEO ; Ji-yeon LEE
Journal of Korean Medical Science 2024;39(13):e120-
Background:
A healthcare system’s collapse due to a pandemic, such as the coronavirus disease 2019 (COVID-19), can expose healthcare workers (HCWs) to various mental health problems. This study aimed to investigate the impact of the COVID-19 pandemic on the depression and anxiety of HCWs.
Methods:
A nationwide questionnaire-based survey was conducted on HCWs who worked in healthcare facilities and public health centers in Korea in December 2020. Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure depression and anxiety. To investigate factors associated with depression and anxiety, stepwise multiple logistic regression analysis was performed.
Results:
A total of 1,425 participating HCWs were included. The mean depression score (PHQ-9) of HCWs before and after COVID-19 increased from 2.37 to 5.39, and the mean anxiety score (GAD-7) increased from 1.41 to 3.41. The proportion of HCWs with moderate to severe depression (PHQ-9 ≥ 10) increased from 3.8% before COVID-19 to 19.5% after COVID-19, whereas that of HCWs with moderate to severe anxiety (GAD-7 ≥ 10) increased from 2.0% to 10.1%. In our study, insomnia, chronic fatigue symptoms and physical symptoms after COVID-19, anxiety score (GAD-7) after COVID-19, living alone, and exhaustion were positively correlated with depression. Furthermore, post-traumatic stress symptoms, stress score (Global Assessment of Recent Stress), depression score (PHQ-9) after COVID-19, and exhaustion were positively correlated with anxiety.
Conclusion
In Korea, during the COVID-19 pandemic, HCWs commonly suffered from mental health problems, including depression and anxiety. Regularly checking the physical and mental health problems of HCWs during the COVID-19 pandemic is crucial, and social support and strategy are needed to reduce the heavy workload and psychological distress of HCWs.
8.Characteristics of Fetal Deaths due to Con genital Anomalies in Korea and Annual Trends from 2009-2020: A Retrospective Study in Korea
Young Hwa SONG ; Jun Suk OH ; Jung Min YOON ; Kyung Ok KO ; Sung Ki LEE ; Tae Yoon KIM ; Jae Woo LIM
Perinatology 2024;35(3):92-101
Objective:
Research on fetal mortality due to congenital anomalies is insufficient, particularly that utilizing data specific to South Korea. Thus, we aimed to investigate the characteristics and risk factors for fetal death due to congenital anomalies in Korea.
Methods:
Fetal deaths registered from 2009-2020 with Statistics Korea were assessed. Fetal charac teristics included gestational age, body weight, sex, and multiple fetuses, while maternal characteri stics included age, educational level, nationality, and place of residence. Risk factors for fetal death were analyzed using simple comparison and logistic regression. Changes in fetal mortality by year were examined using Poisson regression analysis.
Results:
A total of 37,928 fetal deaths occurred, among which 3,758 were classified as congenital anomaly, 710 as non-congenital anomaly, and 33,460 as unknown cause. Fetal mortality for gesta tional weeks 20 to 27 and ≥28 were 75.3% and 24.7%, respectively. The proportion of congenital anomalies among fetal deaths during these gestational age periods is 11.3% and 5.8%. Multiple fetuses, maternal age of <20 years or ≥40 years were identified as risk factors for fetal death due to congenital anomalies. Among the top 30 causes, covering 97.5% of all deaths, unspecified causes were 88.2%, congenital malformations 8.2%, and other causes 2.0%, respectively. Fetal mortality and deaths from congenital anomalies exhibited downward trends.
Conclusion
Fetal deaths due to congenital anomalies showed a decreasing trend, but the risks, such as multiple fetuses and advanced maternal age are increasing in Korea. Therefore, careful monitoring of fetal deaths due to congenital anomalies are essential.
9.Development of the Korean Quality Improvement Platform in Surgery (K-QIPS) program: a nationwide project to improve surgical quality and patient safety
Jeong-Moo LEE ; In Woong HAN ; Oh Chul KWON ; Hye Rim SEO ; Jipmin JUNG ; So Jeong YOON ; Ahram HAN ; Juhan LEE ; Soo Young LEE ; Hoseok SEO ; Wooil KWON ; Bang Wool EOM ; In-Seob LEE ; Ji Won PARK ; Hae Won LEE ; Ho Kyoung HWANG ; Suk-Hwan LEE ; Eung Jin SHIN ; Woo Yong LEE
Annals of Surgical Treatment and Research 2024;107(6):305-314
Purpose:
Improvements in surgical quality and patient safety are critical components of the healthcare system. Despite excellent cancer survival rates in Korea, there is a lack of standardized postoperative complication management systems.To address this gap, the Korean Surgical Society initiated the development of the Korean Quality Improvement Platform in Surgery (K-QIPS) program.
Methods:
K-QIPS was successfully launched in 87 general hospitals. This nationwide surgical quality improvement program covers 5 major surgical fields: gastric surgery, colorectal surgery, hepatectomy and liver transplantation, pancreatectomy, and kidney transplantation.
Results:
Common and surgery-specific complication platforms will be developed, and the program will work toward the implementation of an artificial intelligence-based complication prediction system and the provision of evidence-based feedback to participating institutions. K-QIPS represents a significant step toward improving surgical quality and patient safety in Korea.
Conclusion
This program aims to reduce postoperative complications, mortality, and medical costs by providing a standardized platform for complication management and prediction. The successful implementation of this nationwide project may provide a good model for other countries that are required to improve surgical outcomes and patient care.
10.The Third Nationwide Korean Heart Failure III Registry (KorHF III):The Study Design Paper
Minjae YOON ; Eung Ju KIM ; Seong Woo HAN ; Seong-Mi PARK ; In-Cheol KIM ; Myeong-Chan CHO ; Hyo-Suk AHN ; Mi-Seung SHIN ; Seok Jae HWANG ; Jin-Ok JEONG ; Dong Heon YANG ; Jae-Joong KIM ; Jin Oh CHOI ; Hyun-Jai CHO ; Byung-Su YOO ; Seok-Min KANG ; Dong-Ju CHOI
International Journal of Heart Failure 2024;6(2):70-75
With advancements in both pharmacologic and non-pharmacologic treatments, significant changes have occurred in heart failure (HF) management. The previous Korean HF registries, namely the Korea Heart Failure Registry (KorHF-registry) and Korean Acute Heart Failure Registry (KorAHF-registry), no longer accurately reflect contemporary acute heart failure (AHF) patients. Our objective is to assess contemporary AHF patients through a nationwide registry encompassing various aspects, such as clinical characteristics, management approaches, hospital course, and long-term outcomes of individuals hospitalized for AHF in Korea. This prospective observational multicenter cohort study (KorHF III) is organized by the Korean Society of Heart Failure. We aim to prospectively enroll 7,000 or more patients hospitalized for AHF at 47 tertiary hospitals in Korea starting from March 2018. Eligible patients exhibit signs and symptoms of HF and demonstrate either lung congestion or objective evidence of structural or functional cardiac abnormalities in echocardiography, or isolated right-sided HF. Patients will be followed up for up to 5 years after enrollment in the registry to evaluate long-term clinical outcomes. KorHF III represents the nationwide AHF registry that will elucidate the clinical characteristics, management strategies, and outcomes of contemporary AHF patients in Korea.

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