1.Associated factors of osteoporosis and the impact of osteoporosis on all-cause mortality in incident hemodialysis older patients
Seunghye LEE ; Yoomee KANG ; Yu Ah HONG ; Sung Joon SHIN ; Soon Hyo KWON ; Sungjin CHUNG ; Young Youl HYUN ; Sang Heon SONG ; Jae Won YANG ; Won Min HWANG ; Jang-Hee CHO ; Kyung Don YOO ; In O SUN ; Gang-Jee KO ; Byung Chul YU ; Hyunsuk KIM ; Woo Yeong PARK ; Tae Won LEE ; Dong Jun PARK ; Eunjin BAE ;
Kidney Research and Clinical Practice 2026;45(1):110-119
Background:
With the aging population and advancements in medical care worldwide, the number of older patients with end-stage kidney disease continues to rise. This study aimed to identify factors associated with osteoporosis and osteopenia in older patients undergoing incident hemodialysis and assess their impact on mortality.
Methods:
We analyzed a large multicenter retrospective cohort of patients aged ≥70 years undergoing incident hemodialysis to identify factors associated with osteoporosis using logistic regression analysis and to assess the association of death with osteoporosis and osteopenia using Cox multivariable analysis.
Results:
Among 710 patients, 39.0% and 19.6% had osteoporosis and osteopenia, respectively. Osteoporosis was significantly associated with female sex, a history of fractures, and the absence of phosphate binder use. During a median follow-up of 36.8 months, 348 participants (58.8%) died. Mortality rates were the highest in the osteoporosis group (79.8%), followed by the osteopenia (77.2%) and normal bone mineral density (BMD) groups (35.2%). Cox regression analysis revealed that even after adjusting for covariates, the osteoporosis group was significantly associated with a higher mortality risk than the normal BMD group. Osteoporosis at the start of hemodialysis was significantly associated with higher mortality.
Conclusion
We should consider the importance of bone health in patients undergoing incident hemodialysis and pay attention to the use of phosphate binders and fracture prevention.
2.Impact of obesity on renal function in elderly Korean adults: a national population-based cohort study
Jihyun YANG ; Hui Seung LEE ; Chi-Yeon LIM ; Hyunsuk KIM ; Sungjin CHUNG ; Soon Hyo KWON ; Jang-Hee CHO ; Kyung Don YOO ; Woo Yeong PARK ; In O SUN ; Byung Chul YU ; Gang-Jee KO ; Jae Won YANG ; Won Min HWANG ; Sang Heon SONG ; Sung Joon SHIN ; Yu Ah HONG ; Eunjin BAE ; Young Youl HYUN
Kidney Research and Clinical Practice 2026;45(1):65-76
Background:
Obesity is a well-known risk factor for chronic kidney disease and its progression. However, the impact of obesity on the renal function of the elderly population is uncertain. We investigated the association between obesity and renal outcomes in the elderly.
Methods:
We analyzed 130,504 participants from the Korean National Health Insurance Service-Senior cohort. Obesity was classified according to body mass index (BMI), sex-specific waist circumference (WC), and the presence of metabolic syndrome. The primary outcome was renal function decline, defined as a decline in the estimated glomerular filtration rate (eGFR) of at least 50% from baseline or new-onset end-stage renal disease.
Results:
During a follow-up period of 559,531.1 person-years (median, 4.3 years), 2,486 participants (19.0%; incidence rate of 4.44 per 1,000 person-years) showed renal function decline. A multivariate Cox proportional hazards model revealed that BMI/WC was not associated with renal function decline. However, the group with metabolic syndrome had a significantly increased risk of renal function decline compared to the group without metabolic syndrome (adjusted hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.13–1.36). Compared with the non-metabolic syndrome group, the adjusted HRs (95% CI) for participants with one through five components were 0.96 (0.84–1.11), 1.10 (0.96–1.27), 1.24 (1.06–1.45), 1.37 (1.12–1.66), and 1.99 (1.42–2.79), respectively (p for trend < 0.001).
Conclusion
In elderly Korean adults, metabolic syndrome and the number of its components were associated with a higher risk of renal function decline, but BMI or WC was not significant.
3.Is Hip Center Elevation an Acceptable Choice for Total Hip Arthroplasty for Legg-Calvé-Perthes Disease? Perioperative Complications and Patient-Reported Outcomes
Min Uk DO ; Kyeong Baek KIM ; Sang-Min LEE ; Jae Jin KIM ; Kuen Tak SUH ; Won Chul SHIN
Clinics in Orthopedic Surgery 2026;18(1):30-39
Background:
When positioning the acetabular component for total hip arthroplasty (THA) in patients with sequelae of LeggCalvé-Perthes disease (LCPD), elevating the center of rotation (COR) of the hip is often unavoidable. We aimed to compare the outcomes between the preserved and elevated COR groups in patients with sequelae of LCPD.
Methods:
We enrolled 53 patients who underwent primary THA for sequelae of LCPD between 2006 and 2019. Patients were divided into 2 groups based on the postoperative COR position: 19 in the preserved COR group and 34 in the elevated COR group.The mean elevation of COR was 2.7 mm (range, 0–5.0 mm) in the preserved COR group and 8.1 mm (range, 6.0–12.0 mm) in the elevated COR group. Radiological outcomes, such as osteolysis and implant loosening, were evaluated. Additionally, reoperation, perioperative complications, limping gait, pelvic obliquity, and the modified Harris hip score (mHHS) were assessed.
Results:
There were no significant differences in radiological or clinical outcomes between the 2 groups. Neither osteolysis nor implant loosening was observed, and no reoperations were required. Intraoperative periprosthetic femoral fractures occurred in 3 cases (6%), but no cases of sciatic nerve palsy were observed. Residual limping gait was noted in 10 patients (19%), and pelvic obliquity persisted in 8 patients (15%). At the last follow-up, the mean mHHS was 89.2.
Conclusions
The 5–17-year follow-up results of primary cementless THA in patients with sequelae of LCPD were satisfactory.Furthermore, a moderate elevation of the COR, with a mean of 8.1 mm (range, 6.0–12.0 mm), did not significantly affect the outcomes of THA in these patients. Therefore, a moderate elevation of the COR can be considered an acceptable option for patients undergoing THA with sequelae of LCPD.
4.Optimal use and cycling strategies of Janus kinase inhibitors in ulcerative colitis: current evidence and clinical implications from the KASID Guidelines Task Force Team
Seung Min HONG ; Dong Hyun KIM ; June Hwa BAE ; Seung Yong SHIN ; Eun Mi SONG ; Ji Eun KIM ; Young Joo YANG ; Jiyoung YOON ; Sang-Bum KANG ; Eun Soo KIM ; Seong-Eun KIM ; Seong-Jung KIM ; Jun LEE ; Soo-Young NA ; Soo Jung PARK ; Sang Hyoung PARK ; Miyoung CHOI ; Myung Ha KIM ; Won MOON ; Sung-Ae JUNG ;
Intestinal Research 2026;24(1):27-37
Janus kinase (JAK) inhibitors are an important treatment option for ulcerative colitis, providing rapid onset of action, oral administration, and efficacy even after biologic failure. The 3 approved agents—tofacitinib, filgotinib, and upadacitinib—differ in JAK isoform selectivity, leading to clinically meaningful differences in efficacy and safety. Evidence from network meta-analyses, clinical trials, and real-world studies consistently shows that upadacitinib provides the highest efficacy for induction and maintenance of remission, whereas filgotinib demonstrates the most favorable safety profile. The strong efficacy of upadacitinib and tofacitinib is particularly relevant in patients with severe disease, including acute severe ulcerative colitis, and upadacitinib maintains high efficacy regardless of prior advanced therapy exposure. JAK inhibitors also benefit extraintestinal manifestations. Although risks such as herpes zoster, serious infection, thromboembolism, and major cardiovascular events differ among agents, long-term data suggest generally acceptable safety when used appropriately. Intraclass JAK-to-JAK cycling is feasible, with about half of patients achieving steroid-free clinical remission in retrospective cohorts. Based on mechanistic, clinical, and real-world evidence, filgotinib may be a first-line option for patients with lower disease activity or when safety is a priority, whereas upadacitinib or tofacitinib may be preferred in higher disease activity. Strategically selecting agents may improve durability and outcomes.
5.Whole-Exome Sequencing Improves Risk Assessments of Adult Moyamoya Disease
Eun Pyo HONG ; Eun Jin HA ; Dong Hyuk YOUN ; Yuwhan CHUNG ; Kang Min KIM ; Sung Ho LEE ; Won-Sang CHO ; Hyun-Seung KANG ; Jin Pyeong JEON ; Jeong Eun KIM ;
Journal of Clinical Neurology 2026;22(2):160-172
Background:
and Purpose Whole-exome sequencing (WES) is a valuable tool for identifying causative mutations in adult moyamoya disease (MMD), thereby advancing our understanding of the genetic mechanisms underlying this condition. Here, we conducted the first WESbased association study aimed at identifying genetic modifiers implicated in MMD.
Methods:
This WES study involved 160 patients with MMD and 189 controls from a multicenter hospital-based biobank, and evaluated combined annotation-dependent depletion (CADD) scores. Mutant-allele frequencies were compared in 369,121 individuals derived from the UK Biobank (UKB) WES. Mutant-allele risk scores (MARSs) were created based on WESidentified mutations. Gene-based association analyses and pooled analyses in East-Asian populations were further performed.
Results:
Fourteen mutations reached the genome-wide significance criterion (p<5×10-8 ), among which the p.R4810K mutation in the ring finger protein 213 gene (RNF213) showed the strongest significance (odds ratio=117.4, p=8.54×10-24 ). Notably, two mutations—p.G576S (alpha-glucosidase [GAA]) and p.D54N (charged multivesicular body protein 6 [CHMP6])— exhibited high CADD scores of 32 and 25, respectively, whereas the RNF213 p.R4810K mutation demonstrated a moderate deleteriousness score of 10.63. Fourteen mutations exhibited significant differences in allele frequencies between patients and UKB controlled data (p<1×10-8 ).The MARS9 model (incorporating nine missense mutations) showed better predictability for MMD (90.89%). The analysis of gene-based associations revealed four candidate genes: GAA, RNF213, CHMP6, and CARD14 (p=5×10-19 to 4×10-7 ). The subsequent pooled analyses validated four mutations in East Asian populations: p.V1195M, p.D1331G, p.S2334N, and p.R4810K (p<3×10-8 ).
Conclusions
This pioneering study has corroborated the significance of p.R4810K and identified several causative mutations predisposing patients to MMD, which helps to improve the understanding of its polygenetic nature.
6.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.
7.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.
8.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.
9.Comparative Transcriptomic Profiling of Mesenchymal Stem Cells from Distinct Tissue Origins and Isolation Methods Highlights the Stability and Immunomodulatory Signature of Umbilical Cord-Derived Smumf Cells
Min Ji LEE ; Kyungtaek PARK ; Sungho WON ; Chris Hyunchul JO
Tissue Engineering and Regenerative Medicine 2026;23(1):157-173
BACKGROUND:
Mesenchymal stem cells (MSCs) derived from bone marrow (BM), adipose tissue (AD), and umbilical cord (UC) exhibit therapeutic potential in regenerative medicine. However, their properties, including transcriptomic profiles, vary based on tissue origin, passage stage, and isolation method, complicating their clinical standardization.Addressing these unresolved differences requires comprehensive approaches, such as RNA sequencing, to analyze transcriptomic profiles in detail.
METHODS:
In this study, RNA-seq was employed to analyze MSC transcriptomes from BM, AD, and UC tissues. UC MSCs were isolated using enzymatic digestion or the Minimal Cube Explant (MCE) method (smumf cells), and transcriptomes of early (P3–4) and late (P10) passages of smumf cells were compared. Differentially expressed genes (DEGs) were identified, followed by transcription factor (TF) and pathway analyses.
RESULTS:
Fetal MSCs (UC and smumf cells) exhibited distinct transcriptomic profiles compared to adult MSCs (BM and AD), with 2,208 upregulated and 2,594 downregulated DEGs. Key transcription factors, such as E2F1 and NF-jB1, and pathways, including glycolysis, cholesterol biosynthesis, and TNF-a signaling, were enriched in fetal MSCs. smumf cells demonstrated transcriptomic stability between early and late passages, with only 12 DEGs identified. Additionally, smumf cells showed enhanced innate immune responses and cholesterol metabolism compared to enzymatically isolated UC MSCs.
CONCLUSION
This study provides a comprehensive transcriptomic comparison of MSCs, highlighting the superior transcriptional stability, immunomodulatory capacity, and metabolic flexibility of fetal MSCs, particularly smumf cells. These findings underscore their potential as a reliable cell source for therapeutic applications and encourage further exploration of their clinical application.
10.Serial KL-6 Changes in PD-1/PD-L1 Inhibitor-Related Pneumonitis in Non-small Cell Lung Cancer: A Single-Center Prospective Pilot Study
Jae Kyeom SIM ; Juwhan CHOI ; Sung Won CHANG ; Sang Hyuk KIM ; Jee Youn OH ; Kyung Hoon MIN ; Gyu Young HUR ; Hwan Seok YONG ; Jae Jeong SHIM ; Sung Yong LEE
Tuberculosis and Respiratory Diseases 2026;89(2):257-265
Background:
Programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) inhibitors are effective treatments for non-small cell lung cancer (NSCLC), but their use can lead to severe pneumonitis. This study aims to evaluate the utility of Krebs von den Lungen-6 (KL-6) for predicting and diagnosing PD-1/PD-L1 inhibitor-related pneumonitis in NSCLC patients.
Methods:
We conducted a prospective observational study at a university-affiliated tertiary hospital in Korea from February 2022 to June 2023. Baseline KL-6 levels were measured immediately before initiating PD-1/PD-L1 inhibitor therapy. In patients who developed pneumonitis, KL-6 levels were monitored every 1–2 weeks from the onset of pneumonitis. For patients without pneumonitis, KL-6 levels were measured every 6 weeks. We compared clinical characteristics and serial KL-6 levels between the pneumonitis and non-pneumonitis groups.
Results:
Eighteen patients were enrolled, with 11 developing pneumonitis. Baseline KL-6 levels did not significantly differ between the two groups (261 U/mL in the pneumonitis group vs. 373 U/mL in the non-pneumonitis group, p=0.375). In the pneumonitis group, KL-6 levels generally showed an upward trend, with a median of 412 U/mL at pneumonitis onset. Conversely, KL-6 levels in the non-pneumonitis group showed no clear overall change.
Conclusion
In this pilot study, baseline KL-6 was not clearly linked to PD-1/PD-L1 inhibitor-related pneumonitis in NSCLC patients. However, increases in KL-6 levels post-baseline were more frequently observed in patients who developed pneumonitis, including cases of all-cause pneumonitis.

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