1.Cardiovascular outcomes in patients with obstructive sleep apnea: a 15-year nationwide population-based study
Sung-Won KIM ; Donghyun KIM ; Yisik KIM ; Kyoung-Suk RHEE ; Sunhwa KIM ; Lae-Young JUNG
International Journal of Arrhythmia 2026;27(1):e6-
Background:
and Objective: Obstructive sleep apnea (OSA) is increasingly recognized as a risk factor for cardiovascular diseases. However, long-term population-based evidence across a broad range of cardiovascular outcomes, particularly conduction system disorders, remains limited. We investigated the 15-year cardiovascular outcomes in patients with OSA using a large-scale nationwide cohort.
Methods:
This retrospective cohort study used the Korean National Health Insurance Service database, including 547,749 patients diagnosed with OSA and 2,282,415 matched controls between 2002 and 2020. Following exclusion criteria and 1:1 propensity score matching, 541,812 individuals were included in each group. The primary outcomes were incidence of atrial fibrillation (AF), premature beats, ventricular arrhythmias, atrioventricular (AV) block, sinus node dysfunction, heart failure, ischemic heart disease (IHD), and stroke. Cumulative incidence was assessed using Kaplan-Meier survival curves. Hazard ratios (HRs) were estimated using Cox proportional hazards models adjusted for relevant covariates.
Results:
Over a 15-year follow-up period, the OSA group exhibited significantly higher incidence rates for all cardiovascular outcomes than controls. In the matched cohort, adjusted HR were elevated for AF (1.82 [1.77–1.87]), premature beats (2.25 [2.17–2.34]), ventricular arrhythmias (1.81 [1.64–1.99]), AV block (1.81 [1.64–1.99]), sinus node dysfunction (2.22 [1.96–2.50]), heart failure (1.43 [1.39–1.48]), IHD (1.54 [1.52–1.56]), and stroke (1.20 [1.18–1.22]) (all P < 0.0001).
Conclusions
OSA was independently associated with an increased long-term risk of various cardiovascular outcomes, including arrhythmias, ischemic events, and conduction system disorders. This supports the importance of early identification and longitudinal management of cardiovascular risk in this population.
2.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.
3.Delayed Bleeding With Variable Presentations in Implant-Based Breast Reconstruction During Adjuvant Ado-Trastuzumab Emtansine (Kadcyla) Therapy: Two Case Reports
Seong Jun RYU ; Young Seok KIM ; In Sik YUN ; Kyunghyun MIN ; Joon JEONG ; Tai Suk ROH
Journal of Breast Cancer 2026;29(2):192-201
Ado-trastuzumab emtansine (T-DM1) is an effective adjuvant therapy for human epidermal growth factor receptor 2-positive breast cancer; however, its surgical safety profile remains unclear. We observed delayed bleeding with variable and often subtle clinical manifestations during implant-based breast reconstruction (IBBR). Two patients who received adjuvant T-DM1 therapy after IBBR were retrospectively reviewed. The patient in Case 1 developed a recurrent seroma and liquefied hematoma requiring repeated aspirations, with platelet counts decreasing from 218 × 109 /L to 33 × 109 /L before expander removal.The patient in Case 2 experienced an acute massive hematoma on postoperative day (POD) 2, prior to T-DM1 initiation, which resolved after re-exploration; a temporally distinct delayed hemorrhagic event occurred on POD 175 during T-DM1 therapy after radiotherapy, accompanied by a platelet nadir of 34 × 109 /L. Both patients required plateletpheresis and prolonged drainage. Delayed bleeding during T-DM1 therapy may reflect a combination of hematological suppression and vascular vulnerability. Therefore, vigilant surveillance and cautious postoperative rehabilitation are warranted.
4.Establishing an Active Vaccine Safety Surveillance System Using Large Scale Databases in Korea: Lessons and Scalable Insights for Global Application
Jin Gu YOON ; Eliel NHAM ; Yu Jung CHOI ; Min Joo CHOI ; Won Suk CHOI ; Young Kyung YOON ; Yu Bin SEO ; Hakjun HYUN ; Jung Yeon HEO ; Jin-Soo LEE ; Chung-Jong KIM ; Ji Yun NOH ; Joon Young SONG ; Hee Jin CHEONG
Journal of Korean Medical Science 2026;41(1):e47-
Vaccines are highly effective, but rare or delayed adverse events following immunization (AEFIs) require post-licensure surveillance beyond clinical trials. Korea lacks a comprehensive, active, database-based framework, yet key assets exist: nationwide claims databases (National Health Insurance Service/Health Insurance Review and Assessment Service), the national immunization registry (Korea Disease Control and Prevention Agency’s Immunization Registry Information System) for National Immunization Program (NIP) and non-NIP vaccines, and increasingly standardized hospital electronic health records.We propose a federated, code to data architecture with data linkages between these data.Implementation should adopt a common data model (CDM), standardized case definitions, latency accounting, and transparent public reporting under strong privacy governance. Major challenges include multi step administrative approvals for data linkage, incomplete capture of adult non-NIP vaccinations, heterogeneous hospital data structures, and strict data protection constraints. Strategic priorities are to streamline statutory and administrative processes for public health use, mandate or enable claims-based capture of adult vaccinations, enhance CDM based interoperability, and develop secure hubs for aggregated outputs. With these measures, Korea will be well positioned to establish a scalable active surveillance system capable of detecting rare AEFIs, supporting transparent and evidence-based communication, and ensuring equitable injury compensation grounded in domestic data.
5.Current Clinical Perspectives on Rosacea Management: Insights From a Korean Multicenter Expert Opinion Survey
Bo Ri KIM ; Sejin OH ; Ju Hee HAN ; Jimyung SEO ; Hyun-Min SEO ; Soon-Hyo KWON ; Hoon CHOI ; Jung U SHIN ; Jae We CHO ; Boncheol Leo GOO ; Jung-Im NA ; Dong Hun LEE ; Chun Pill CHOI ; HaeWoong LEE ; Joo Yeon KO ; Hwa Jung RYU ; Nark-Kyoung RHO ; Hyunjo KIM ; Ga-Young LEE ; Jong Hee LEE ; Nala SHIN ; Sang Ju LEE ; Suk Bae SEO ; Geun Soo LEE ; Hei Sung KIM ; Chang-Hun HUH
Annals of Dermatology 2026;38(1):42-50
Background:
Rosacea is a chronic inflammatory skin disorder characterized by erythema, papules, ocular symptoms, and heightened sensitivity. Patients with neurogenic symptoms such as burning or stinging remain particularly difficult to manage. Current guidelines often underrepresent energy-based devices (EBDs), pigmentary sequelae, psychosocial burden, and ocular comorbidities.
Objective:
To examine Korean dermatologists’ expert perspectives on rosacea management, focusing on skin sensitivity, neurogenic symptoms, pigmentary changes, psychosocial impact, ocular involvement, and EBD use.
Methods:
A web-based, 29-item survey was administered to 25 board-certified Korean dermatologists (May–June 2025). Quantitative and qualitative responses were analyzed.
Results:
Erythematotelangiectatic and papulopustular phenotypes with sensitivity skin predominated. EBDs (pulsed dye laser, intense pulsed light) were frequently used but limited by cost and sensitivity issues. Neurogenic symptoms were recognized but rarely treated with neuromodulators. Post-inflammatory hyperpigmentation was infrequent, yet monitoring was inconsistent.Psychosocial and ocular aspects were acknowledged but seldomly systematically addressed.Respondents expressed interest in emerging adjunctive treatments such as cold plasma, skin boosters, and holistic care approaches.
Conclusion
Korean dermatologists adopt individualized strategies for rosacea, yet practice gaps remain regarding neurogenic symptoms, pigmentary complications, and psychosocial and ocular comorbidities. Findings support the need for updated multidisciplinary, phenotype-driven guidelines aligned with real-world practice.
6.Revision of Nutrition Quotient for Korean preschool children: NQ-P 2021
Hyo-Jeong HWANG ; Ki Nam KIM ; Young-Suk LIM ; Ji-Yun HWANG ; Hye-Young KIM ; Jung-Sug LEE
Journal of Nutrition and Health 2026;59(1):45-62
Purpose:
This study was conducted to revise the Nutrition Quotient for Preschool children (NQ-P), a tool for evaluating the overall dietary quality and eating behavior among Korean preschool-aged children.
Methods:
At the first stage, 20 items for assessing dietary behavior were selected based on the previous NQ-P checklist, incorporating the results of the Seventh Korea National Health and Nutrition Examination Survey, national nutrition policies, dietary guidelines, and recent literature reviews. A pilot study was conducted with 100 preschool children residing in Seoul and Gyeonggi Province, using an 18-item checklist. After exploratory factor analysis and expert consultation, 15 items were finalized for use in nationwide survey checklists. The nationwide survey was conducted with a stratified sample of 800 preschool children across six metropolitan cities. Confirmatory factor analysis was used to revise the NQ-P 2021 and make it suitable for the structural equation model.
Results:
The NQ-P 2021 was developed using 15 checklist items organized into three factors:balance (7 items), moderation (4 items), and practice (4 items). The standardized path coefficients were used as item weights to determine the nutrition quotients. The weights of balance, moderation, and practice were 0.40, 0.15, and 0.45, respectively. In the nationwide survey, the mean NQ-P 2021 score was 59.67. The average scores for balance, moderation, and practice were 51.00, 62.45, and 66.46, respectively.
Conclusion
The revised NQ-P 2021 provides a validated and practical tool for assessing the dietary quality and eating behaviors of preschool children in Korea.
7.Impact of COVID-19 on the Profitability of General Hospitals in Korea
Jun Young PARK ; Tae Hyun KIM ; Suk-Yong JANG ; Sang Gyu LEE
Journal of Preventive Medicine and Public Health 2026;59(1):46-55
Objectives:
This study was performed to quantify the impact of coronavirus disease 2019 (COVID-19) on hospital profitability in Korea by analyzing changes in the medical revenue-to-profit ratio (MRPR) and net income before reserve fund allocation (NIBR) before and after the pandemic onset. Additionally, it examined how financial outcomes varied by hospital ownership, geographic location, and type (secondary or tertiary), providing insights into the financial resilience of various hospital types during public health crises.
Methods:
We conducted a longitudinal analysis using publicly available financial disclosure data from 243 general hospitals in Korea (2016–2022). We then performed a quadrant analysis to classify hospitals based on changes in MRPR and NIBR, identifying patterns of financial impact. For inferential analysis, we employed linear mixed-effects models incorporating a difference-in-differences framework, enabling estimation of both time-varying and hospital-specific effects.
Results:
Following the onset of COVID-19, MRPR declined significantly, reaching −10.62% in 2020. NIBR initially dropped but later increased, reaching 21.09 billion Korean won per 100 beds in 2022. Quadrant analysis revealed substantial heterogeneity in financial responses, with national/public hospitals experiencing the most severe MRPR decline, whereas educational foundation and medical corporation hospitals displayed stronger financial recovery. Regression results confirmed significant interactions between outcomes after COVID-19 onset and hospital ownership type, indicating differential financial impacts across hospital categories.
Conclusions
The findings highlight the uneven financial effects of COVID-19 on Korean hospitals, emphasizing the importance of targeted government financial support. Policy measures should prioritize structural financial reforms to ensure hospital sustainability beyond short-term crisis management.
8.The onco-bariatric paradigm: a tri-phasic metabolic obesity framework for synergizing glucagon-like peptide-1 receptor agonists and metabolic bariatric surgery
Dong Jin PARK ; Yoonhong KIM ; Dongjae JEON ; Young Suk PARK ; Kyung Won SEO ; Ki Hyun KIM
Kosin Medical Journal 2026;41(1):3-8
Obesity is a chronic, progressive neuroendocrine disease that warrants a shift toward an “onco-bariatric” treatment paradigm. This study introduces the tri-phasic metabolic obesity (TPMO) framework, which integrates glucagon-like peptide-1 receptor agonists (GLP-1 RAs) with metabolic bariatric surgery (MBS). Recent clinical and economic evidence—including findings from the Indiana multicenter study and the Highmark Health analysis—was reviewed to evaluate the effectiveness of the TPMO model in improving surgical and metabolic outcomes. The TPMO framework streamlines the patient journey through three synergistic phases. In the neoadjuvant phase, a 4–8-week course of GLP-1 RAs reduces liver volume and visceral fat, thereby improving surgical access, provided that treatment is discontinued 1 week before surgery to mitigate aspiration risk. During the core surgery phase, MBS provides a definitive metabolic reset and remains the most cost-effective treatment, yielding an average savings of $11,689 per patient over 2 years compared with medication alone. In the adjuvant phase, pharmacotherapy—used by 17.2% of post-bariatric patients—counteracts metabolic adaptation and supports sustained weight loss, while a high-protein intake (≥1.2 g/kg/day) is essential for preserving lean body mass. The TPMO framework represents a precision-based, synergistic standard of care designed to promote durable, cost-effective long-term metabolic health within the onco-bariatric paradigm.
9.Development and Validation of an Analytical Method for the Simultaneous Determination of Three Marker Compounds in Wikstroemia trichotoma
Min-Ji KEEM ; Taek-Hwan KWON ; Beom-Geun JO ; Sangho CHOI ; Jin-Hyub PAIK ; Young Suk JUNG ; Eun-Ju JEONG ; Su-Nam KIM ; Min Hye YANG
Natural Product Sciences 2026;32(1):84-92
The Wikstroemia genus is highly regarded in traditional Asian medicine for its diverse therapeutic applications, including the treatment of inflammatory and infectious conditions. Among its members,Wikstroemia trichotoma (Thunb.) Makino remains a promising medicinal resource which is yet to be chemicallycharacterized. To ensure the chemical consistency of W. trichotoma, we developed and validated the first HPLC method for the simultaneous quantification of three major marker compounds: chlorogenic acid (1), miconioside B (2), and matteucinol 7-O-apiofuranosyl(1→6)-glucopyranoside (3). Chromatographic separation was achieved on a C18 column using a gradient elution system of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. Detection was optimized using a photodiode array (PDA) detector at 280 and 325 nm, based on the absorption maxima of the markers. The method was validated in accordance with the International Council for Harmonisation (ICH) and the Ministry of Food and Drug Safety (MFDS) guidelines. The results demonstrated high linearity (r2 > 0.999), with limits of detection and quantitation ranging from 4.28–6.42 and 12.97–19.47 μg/ mL, respectively. Intra- and inter-day precision (% RSD ≤ 1.83%) and accuracy (recoveries of 92.5–101.7%) were within acceptable limits. Quantitative analysis revealed the contents of 1, 2, and 3 in the W. trichotoma extract to be 19.9, 139.8, and 264.9 mg/g, respectively. This study provides a reliable analytical framework for the standardization, quality control, and future pharmacological evaluation of W. trichotoma.
10.Rapamycin mitigates warm ischemiainduced peribiliary fibrosis: A non-transplant experimental model with implications for ischemic cholangiopathy
Hyun Hwa CHOI ; Geun HONG ; Kwang-Woong LEE ; Jae-Yoon KIM ; Jiyoung KIM ; Jaewon LEE ; Su Young HONG ; Suk Kyun HONG ; YoungRok CHOI
Annals of Liver Transplantation 2026;6(1):33-40
Background:
Warm ischemia is a major contributor to ischemic cholangiopathy and non-anastomotic biliary strictures (NAS) after liver transplantation, particularly in donation-after-circulatory-death grafts. However, the isolated impact of warm ischemia on peribiliary fibrosis is difficult to delineate because clinical settings involve overlapping effects of cold ischemia, reperfusion injury, and alloimmunity. This study aimed to establish a non-transplant rat model that isolates warm ischemic biliary injury and to compare the antifibrotic effects of rapamycin and tacrolimus.
Methods:
Warm ischemia was induced in Sprague–Dawley rats by ligating both ends of the peribiliary vascular plexus and the hepatic artery, followed by 30 minutes of portal vein clamping. Rats were randomly assigned to control, tacrolimus (1 mg/kg/day), or rapamycin (1 mg/kg/day) groups (n=15 per group). Serum alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, and total bilirubin were measured serially. Hematoxylin and eosin (H&E) and Sirius red staining were performed at 1, 3, and 6 weeks. Peribiliary fibrosis was quantified using digital image analysis of collagen area fraction.
Results:
Warm ischemia induced acute hepatobiliary injury with transient enzyme elevations, but no significant intergroup differences were observed. Histologically, biliary epithelial proliferation and collagen deposition increased progressively and became prominent at 6 weeks. At this time point, fibrosis ratios differed significantly (overall p=0.002): controls showed the highest fibrosis (4.8%), followed by tacrolimus (2.4%) and rapamycin (1.7%). Both immunosuppressants significantly reduced fibrosis compared with controls (p<0.05), whereas the difference between tacrolimus and rapamycin was not significant.
Conclusion
This warm ischemia model demonstrates that isolated ischemic injury alone can induce progressive peribiliary fibrosis. Rapamycin and tacrolimus attenuated fibrosis, with rapamycin producing the lowest collagen deposition. These findings provide mechanistic insight into ischemic cholangiopathy after liver transplantation—particularly in donation after circulatory death grafts—and underscore the need for further studies using models that incorporate cold ischemia, reperfusion, and alloimmune factors.

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