Background/Aims: The optimal vascular access strategy for very elderly patients initiating hemodialysis (HD) remains unclear. Arteriovenous fistulas (AVFs) offer long-term benefits but may be limited due to vascular aging. This study evaluated vascular access outcomes in patients aged ≥ 80 years. Methods: We conducted a retrospective cohort study using data from the Korean National Health Insurance Service between 2008 and 2019. Patients aged ≥ 80 years who initiated HD with a newly created AVF or arteriovenous graft (AVG) were included. Primary outcomes were primary, assisted primary, and secondary patency. The secondary outcome was all-cause mortality. Outcomes were compared using Kaplan–Meier analysis and multivariable Cox regression. Results: Among 8,487 patients, 5,124 (60.4%) received AVFs (AVF group) and 3,363 (39.6%) received AVGs (AVG group). AVFs were associated with significantly lower rates of patency loss across all definitions. The adjusted hazard ratios (HRs) for AVG vs. AVF were 1.76 (95% confidence interval [CI], 1.67–1.86) for primary patency loss, 1.90 (95% CI, 1.77–2.03) for assisted primary, and 3.18 (95% CI, 2.81–3.61) for secondary patency loss. All-cause mortality was also higher in the AVG group (adjusted HR, 1.24; 95% CI, 1.17–1.30). Conclusions In this large-scale study, AVF use was associated with superior patency and lower mortality compared with AVG in patients aged ≥ 80 years. These findings suggest that AVF remains a beneficial option for appropriately selected elderly patients and that age alone should not be a primary barrier to its creation.

Objective: To classify life stages for companion dogs and cats by identifying clusters in age-specific disease proportions derived from medical records, providing a data-driven foundation for health examination programs. Methods: We collected 505,667 medical records from 82 veterinary facilities in South Korea between 2020 and 2023. Diagnoses were standardized using GPT-4o and S-BioBERT. Following preprocessing, data from 27 facilities yielded 222,706 canine and 39,910 feline records for the final analysis. Principal component analysis and K-means clustering (K = 4) were applied to age-specific disease proportions to identify life stages.The 10 most highest-proportion diagnoses diseases were determined for each cluster. Results: Canine life stages were classified as ≤ 1 year, 2–5 years, 6–10 years, and 11–15+ years.Feline life stages were 1–2 years, 3–8 years, 9–12 years, and 13–15+ years. In dogs, developmental diseases were common in the youngest age group, while chronic diseases were more prevalent in older groups. In cats, oral and urinary diseases were high-ranking, conjunctivitis was most common in the early stage, and chronic diseases increased with age. Conclusions and Relevance: Age-specific diagnosis patterns support four practical life stages for dogs and cats in South Korea. These boundaries can inform evidence-based preventive examination schedules, animal health policy, and pet insurance product design.

Autoimmune hemolytic anemia (AIHA) is a rare immune-mediated disorder in children that can present as primary or secondary to other diseases. Here, we report an unusual case of steroid-refractory warm AIHA in an 11-year-old girl whose condition was ultimately cured after removal of a benign ovarian tumor. Despite receiving multiple lines of therapy—including corticosteroids, rituximab, cyclosporine, sirolimus, and mycophenolate mofetil—the patient experienced recurrent hemolysis and steroid dependence for nearly four years. Abdominopelvic imaging performed to evaluate fever revealed bilateral ovarian cystic lesions, including a left-sided dermoid cyst. Surgical resection of the tumor led to complete and sustained hematologic remission, with normalization of hemoglobin, bilirubin, and reticulocyte counts, allowing discontinuation of all immunosuppressive agents. No recurrence of hemolysis was observed during 18 months of follow-up. This case highlights the potential for benign ovarian tumors to act as a rare secondary cause of AIHA through paraneoplastic or immune cross-reactive mechanisms. Awareness of such associations is crucial when evaluating pediatric patients with refractory or relapsing AIHA, as identification and removal of an occult tumor may achieve definitive resolution of hemolysis and avoid long-term immunosuppression.

Background: and Purpose: Amyloid-beta (Aβ) plaques are key in Alzheimer’s disease (AD), with Aβ positron emission tomography imaging enabling non-invasive quantification.To address regional Aβ deposition, we developed regional Centiloid scales (rdcCL) and commercialized them through the computed tomography (CT)-based BeauBrain Amylo platform, eliminating the need for three-dimensional T1 magnetic resonance imaging (MRI). Objective: We aimed to establish robust regional Aβ cutoffs using the commercialized BeauBrain Amylo platform and to explore the prevalence of subgroups defined by global, regional, and striatal Aβ cutoffs across cognitive stages. Methods: We included 2,428 individuals recruited from the Korea-Registries to Overcome Dementia and Accelerate Dementia Research project. We calculated regional Aβ cutoffs using Gaussian Mixture Modeling. Participants were classified into subgroups based on global, regional, and striatal Aβ positivity across cognitive stages (cognitively unimpaired [CU], mild cognitive impairment, and dementia of the Alzheimer’s type). Results: MRI-based and CT-based global Aβ cutoffs were highly comparable and consistent with previously reported Centiloid values. Regional cutoffs revealed both similarities and differences between MRI- and CT-based methods, reflecting modality-specific segmentation processes. Subgroups such as global(−)regional(+) were more frequent in non-dementia stages, while global(+)striatal(−) was primarily observed in CU individuals. Conclusions Our study established robust regional Aβ cutoffs using a CT-based rdcCL method and demonstrated its clinical utility in classifying amyloid subgroups across cognitive stages. These findings highlight the importance of regional Aβ quantification in understanding amyloid pathology and its implications for biomarker-guided diagnosis and treatment in AD.

Background: and Purpose: Brain atrophy, characterized by sulcal widening and ventricular enlargement, is a hallmark of neurodegenerative diseases such as Alzheimer’s disease. Visual assessments are subjective and variable, while automated methods struggle with subtle intensity differences and standardization, highlighting limitations in both approaches. This study aimed to develop and evaluate a novel method focusing on cerebrospinal fluid (CSF) regions by assessing segmentation accuracy, detecting stage-specific atrophy patterns, and testing generalizability to unstandardized datasets. Methods: We utilized T1-weighted magnetic resonance imaging data from 3,315 participants from Samsung Medical Center and 1,439 participants from other hospitals. Segmentation accuracy was evaluated using the Dice similarity coefficient (DSC), and W-scores were calculated for each region of interest (ROI) to assess stage-specific atrophy patterns. Results: The segmentation demonstrated high accuracy, with average DSC values exceeding 0.9 for ventricular and hippocampal regions and above 0.8 for cortical regions. Significant differences in W-scores were observed across cognitive stages (cognitively unimpaired, mild cognitive impairment, dementia of Alzheimer’s type) for all ROIs (all, p<0.05). Similar trends were observed in the images from other hospitals, confirming the algorithm’s generalizability to datasets without prior standardization. Conclusions This study demonstrates the robustness and clinical applicability of a novel CSF-focused segmentation method for assessing brain atrophy. The method provides a scalable and objective framework for evaluating structural changes across cognitive stages and holds potential for broader application in neurodegenerative disease research and clinical practice.

Background/Aims: Inaccurate prediction of lymph node metastasis (LNM) may lead to unnecessary surgery following endoscopic resection of T1 colorectal cancer (CRC). We aimed to validate the usefulness of artificial intelligence (AI) models for predicting LNM in patients with T1 CRC. Methods: We analyzed the clinical data, laboratory results, pathological reports, and endoscopic findings of patients who underwent radical surgery for T1 CRC. We developed AI models to predict LNM using four algorithms: regularized logistic regression classifier (RLRC), random forest classifier (RFC), CatBoost classifier (CBC), and the voting classifier (VC). Four histological factors and four endoscopic findings were included to develop AI models. Areas under the receiver operating characteristics curves (AUROCs) were measured to distinguish AI model performance in accordance with the Japanese Society for Cancer of the Colon and Rectum guidelines. Results: Among 1,386 patients with T1 CRC, 173 patients (12.5%) had LNM. The AUROC values of the RLRC, RFC, CBC, and VC models for LNM prediction were significantly higher (0.673, 0.640, 0.679, and 0.677, respectively) than the 0.525 suggested in accordance with the Japanese Society for Cancer of the Colon and Rectum guidelines (vs RLRC, p<0.001; vs RFC, p=0.001; vs CBC, p<0.001; vs VC, p<0.001). The AUROC value was similar between T1 colon versus T1 rectal cancers (0.718 vs 0.615, p=0.700). The AUROC value was also similar between the initial endoscopic resection and initial surgery groups (0.581 vs 0.746, p=0.845). Conclusions AI models trained on the basis of endoscopic findings and pathological features performed well in predicting LNM in patients with T1 CRC regardless of tumor location and initial treatment method.

Background/Aims: The study investigated the incidence, risk factors, and clinical outcomes of chronic antibiotic-refractory pouchitis (CARP) in Korean patients with ulcerative colitis (UC). Methods: This single-center retrospective study included patients with UC who underwent total proctocolectomy with ileal pouch-anal anastomosis at the Asan Medical Center in Korea between January 1987 and December 2022. The primary outcomes were endoscopic remission and pouch failure. The Cox’s proportional hazard model was used to identify the risk factors for CARP. Results: The clinical data of 232 patients were analyzed. The most common cause of surgery was steroid refractoriness (50.9%), followed by dysplasia/colorectal cancer (26.7%). Among 74 patients (31.9%) with chronic pouchitis (CP), 31 (13.4%) had CARP, and 43 (18.5%) had chronic antibiotic-dependent pouchitis (CADP). The most frequent endoscopic phenotype was focal inflammation of the pouch (CP, 47.3%; CARP, 35.5%; CADP, 55.8%). Patients with CARP were less likely to use concomitant probiotics than patients with CADP (29.0% vs 72.1%, p<0.01). The endoscopic remission rate of CP, CARP, and CADP was 14.9%, 9.7%, and 18.6%, respectively.The pouch failure rate associated with CP, CARP, and CADP was 13.5%, 16.1%, and 11.6%, respectively. Current smoking status (adjusted hazard ratio [aHR], 2.96; 95% confidence interval [CI], 1.27 to 6.90; p=0.01) and previous use of biologics/small molecules (aHR, 2.40; 95% CI, 1.05 to 5.53; p=0.04) were significantly associated with CARP development. Conclusions UC patients who were current smokers and previously used biologics/small molecules had a higher risk of developing CARP. Concomitant use of probiotics was less likely to be associated with CARP development.

Purpose: We aimed to evaluate health-related quality of life (HRQoL) in intestinal failure (IF) patients after different modes of intestinal rehabilitation. Methods: HRQoL was assessed using the generic 36-item Short Form Survey (SF-36, ver. 2) and visual analogue scale (VAS) in 6 different areas: diet, sleep, gastrointestinal (GI) symptoms, diarrhea, musculoskeletal pain, and other symptoms. Results: Twenty-two patients completed the questionnaires, of which 7 had received intestinal transplant (ITx), 9 were continuing home total parenteral nutrition (HPN), and 6 had tapered off total parenteral nutrition (TPN). SF-36 physical component summary scores were highest in the ITx group (median, 65.6; interquartile range [IQR], 31.6–80.3) compared to the HPN (median, 48.4; IQR, 44.7–66.3) or tapered group (median, 54.2; IQR, 45.2–61.6). Mental component summary scores were lowest in the ITx group (median, 48.8; IQR, 37.1–63.6), compared to the TPN (median, 60.2; IQR, 41.6–78.5) or tapered group (median, 51.0; IQR, 48.8–56.0). Differences were not significant in all items of the SF-36. VAS scores showed that patients in the ITx group showed the best results in diet (0.9), gastrointestinal (GI) symptoms (1.4), and musculoskeletal pain (2.4). There was a significant difference in sleep (P = 0.036), with the ITx (1.43) and HPN groups (1.33) showing better outcomes compared with the tapered group (4.67). Patients in the tapered group showed the least favorable results in all performance areas, except GI symptoms. Conclusion SF-36 did not show a significant difference between the ITx, HPN, and tapered groups, but VAS showed a significant difference in sleep between groups. Further studies, including serial data, will allow a better understanding of the effects of different modes of intestinal rehabilitation.

Hysteroscopy is particularly valuable for the diagnosis of uterine cavity abnormalities through direct visualization. The development of office hysteroscopy has expanded the range of diagnostic and surgical procedures available. These detailed guidelines include patient counseling and the selection and setting of office hysteroscopy, including room, equipment, and medical staff. Analgesia or local anesthesia is often required in selective office hysteroscopy cases. Cervical dilation and preparation using medical or mechanical methods are required for most diagnostic hysteroscopic procedures. Methods for optimizing visualization and choosing suitable distension media are important for a successful office hysteroscopy. It is crucial to adhere to guidelines to prevent complications, such as vasovagal syncope, cervical trauma, uterine perforation, fluid overload, and embolism. Vaginoscopy can be a good alternative option for alleviating pain, especially in cases where the insertion of a vaginal speculum is expected to be challenging.

Background/Aims: Portal vein thrombosis (PVT) frequently occurs in patients with inflammatory bowel disease (IBD), particularly when influenced by factors such as abdominal infections, IBD flare-ups, or surgical procedures. The implications of PVT range from immediate issues such as intestinal ischemia to long-term concerns including portal hypertension and its complications. However, there is a notable gap in comprehensive studies on PVT in IBD, especially with the increasing incidence of IBD in Asia. This research aimed to evaluate the clinical features and outcomes of PVT in patients with IBD at a leading hospital in South Korea. Methods: This retrospective analysis reviewed adult patients diagnosed with both IBD and PVT from 1989 to 2021 at a renowned South Korean medical center. The study focused on patient characteristics, specifics of PVT, administered treatments, and outcomes, all confirmed through enhanced CT scans. Results: A total of 78 patients met the study’s criteria. Notably, only 20.5% (16/78) were treated with oral anticoagulants; however, a vast majority (96.2%; 75/78) achieved complete radiographic resolution (CRR). When comparing patients receiving anticoagulants to those who did not, a significant preference for anticoagulant use was observed in cases where the main portal vein was affected, as opposed to just the left or right veins (p = 0.006). However, multivariable analysis indicated that neither anticoagulant use nor previous surgeries significantly impacted CRR. Conclusions Patients with IBD and PVT generally had favorable outcomes, regardless of anticoagulant use.