Background: Despite widespread vaccination efforts against severe acute respiratory syndrome coronavirus 2, variants with increased transmissibility or immune evasion continue to emerge, posing a considerable challenge. Understanding the immunological factors associated with coronavirus disease (COVID-19) progression is essential for improving patient management and treatment strategies. We explored the dynamic changes in the peripheral white blood cell (WBC) profile, including T lymphocyte subsets, to assess their potential as predictors of disease severity and progression. Methods: Two hundred fifty-eight patients hospitalized for confirmed COVID-19 were classified into four sub-cohorts based on changes in disease severity over 7 days. WBC parameters, including absolute neutrophil, total lymphocyte, and T cell subset counts, and the neutrophil-to-lymphocyte ratio (NLR) were assessed at admission and after 7 days. Results: Patients with persistent mild-to-moderate illness exhibited a marked increase in the lymphocyte count and a decrease in the NLR over time. In contrast, patients with sustained severe-to-critical illness showed an increasing WBC count without a corresponding increase in the lymphocyte count, in addition to a marked elevation in the NLR. Patients whose condition improved from severe-to-critical to mild-to-moderate illness showed increased cluster of differentiation (CD)3+ and CD4+ T cell counts and an elevated CD4/CD8 ratio, whereas the NLR did not significantly change. Conclusions The early-phase dynamics of T cell subsets may serve as a useful biomarker of disease severity and recovery in patients with COVID-19. Monitoring these immunological changes may help support clinical decision-making and inform the timing of therapeutic interventions.

Olanzapine is a second-generation antipsychotic drug associated with the development of type 2 diabetes. However, the development and remission of diabetes with glutamic acid decarboxylase (GAD) antibody (Ab) positivity related to olanzapine treatment have not been reported. Here, we present the case of a 33-year-old man taking olanzapine who was diagnosed with diabetes with GAD Ab positivity complicated by diabetic ketoacidosis (DKA). After discontinuation of the drug and tight glycemic control, his diabetes remitted, and the GAD Ab became negative spontaneously after 18 months. The classification of diabetes is challenging because of overlapping autoimmune and metabolic features. Olanzapine may have contributed to pancreatic β-cell apoptosis, which could potentially trigger autoimmunity and the development of type 1 diabetes-like features (DKA as the initial presentation, a low C-peptide level, and GAD Ab positivity). The rapid amelioration of hyperglycemia and weight reduction may be responsible for the remission of diabetes after the discontinuation of olanzapine.

Purpose: Radiotherapy is used to reduce the risk of breast cancer recurrence after surgery, but it is a potential cause of secondary cancer. We validated the risk of secondary cancer in primary breast cancer who received radiotherapy compared with those who did not from a matched cohort using a large-scale observational study of the Observational Health Data Sciences and Informatics (OHDSI) data network. Materials and Methods: A retrospective comparative cohort study using propensity score-matched cohorts was performed using two Observational Medical Outcome Partnership common data model databases, from tertiary general hospitals in South Korea. Among female patients who underwent surgery after the diagnosis of breast cancer, the risk of secondary primary malignant occurrence after 1:1 matching was analyzed. Results: Among 27,078 patients with breast cancer, there was no significant difference in the risk of secondary cancer following radiotherapy in 4,426 patients after 1:1 propensity-score matching. Further, there were no significant differences in the sensitivity analysis according to age, latency period, and number of radiation treatments. Conclusion There was no difference in the risk of secondary cancer in the patients diagnosed with breast cancer depending on whether or not radiotherapy was performed after surgery. In the future, it is necessary to analyze including data generated during cancer treatment.

Purpose: Chronic myeloid leukemia (CML) in children, adolescents, and young adults is rare and differs from older adults. This study evaluated the outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) in young Korean CML patients during the tyrosine kinase inhibitor (TKI) era. Materials and Methods: A retrospective analysis of 35 CML patients aged < 40 years who underwent allogeneic HSCT from 2009 to 2019 was conducted using Korean Blood and Marrow Transplantation Registry data. Patients were grouped by age < 20 years at HSCT (group 1, n=15) and 20-40 years at HSCT (group 2, n=20). Survival outcomes including overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS) were analyzed using the Kaplan-Meier method. Results: The median time between diagnosis and HSCT was 8.9 months. All the patients achieved engraftment but platelet recovery was significantly slower in group 1 (p=0.034). Acute and chronic graft-versus-host disease occurred in 54.3% and 34.3%, respectively. Five-year OS, RFS, and EFS rates of total patients were 66.8%, 50.8%, and 47.6%, with better OS was observed in group 1 by multivariable analysis (p=0.048). Disease status at HSCT was a significant predictor of OS (p=0.028), RFS (p=0.003), and EFS (p=0.004). Disease progression occurred in 13 out of 35 patients (37.1%); treatment-related mortality accounted for 63.6% of deaths (7 out of 11). Conclusion When performed at a younger age, allogeneic HSCT result in superior outcome in CML. Achieving remission before HSCT is critical for improved outcomes, highlighting the importance of pretransplant remission via optimal TKI strategies and minimal residual disease monitoring.

Background: and Purpose: To assess the long-term effectiveness, safety, and economic viability of recently approved Alzheimer’s disease (AD) therapies, as well as to evaluate the real-world application of novel diagnostics among AD patients with diverse comorbidities, comprehensive real-world data (RWD) analysis is essential. The Korean JOint RegistrY for ALZheimer’s Treatment and Diagnostics (JOY-ALZ) endeavors to create a registry of RWD derived from clinical practice on new diagnostic methods and therapeutic agents for AD introduced in Korea since 2021. Methods: Participants must fulfill all the following: 1) be at least 19 years old; 2) be actively receiving, scheduled to initiate, or undergoing evaluation for any AD disease-modifying treatment; 3) have completed amyloid positron emission tomography or cerebrospinal fluid AD immunoassay (a positive result is not essential for participation); 4) have a clinical classification of cognitively unimpaired, mild cognitive impairment, or probable AD dementia. Data generated during routine care is segmented into a minimum dataset, extended dataset, and research-only dataset requiring extra consent. Assessments encompass clinical, cognitive, functional, neurobehavioral, neuroimaging, and biomarker evaluations, in addition to systematic monitoring of new AD treatments and their safety.Data are collected and monitored at baseline, at semiannual intervals during the initial 2 years, and then annually up to 2034. To date, 46 medical centers will participate in JOY-ALZ. Conclusions JOY-ALZ is expected to promote understanding of the long-term clinical outcomes, safety, and cost-effectiveness of recently introduced diagnostics and treatments for AD, thereby supporting the progress of precision medicine in AD care and diagnosis.

This study explores the development, roles, and key initiatives of the Regional Environmental Health Centers in Korea, detailing their evolution through four distinct phases and their impact on environmental health policy and local governance. It chronicles the establishment and transformation of these centers from their inception in May 2007, through four developmental stages. Originally named Environmental Disease Research Centers, they were subsequently renamed Environmental Health Centers following legislative changes. The analysis includes the expansion in the number of centers, the transfer of responsibilities to local governments, and the launch of significant projects such as the Korean Children’s Environmental Health Study (Ko-CHENS ). During the initial phase (May 2007–February 2009), the 10 centers concentrated on research-driven activities, shifting from a media-centered to a receptor-centered approach. In the second phase, prompted by the enactment of the Environmental Health Act, six additional centers were established, broadening their scope to address national environmental health issues. The third phase introduced Ko-CHENS, a 20-year national cohort project designed to influence environmental health policy by integrating research findings into policy frameworks. The fourth phase marked a decentralization of authority, empowering local governments and redefining the centers' roles to focus on regional environmental health challenges. The Regional Environmental Health Centers have significantly evolved and now play a crucial role in addressing local environmental health issues and supporting local government policies. Their capacity to adapt and respond to region-specific challenges is essential for the effective implementation of environmental health policies, reflecting geographical, socioeconomic, and demographic differences.

Purpose: To investigate the clinical characteristics of South Korean patients with pericentral retinitis pigmentosa (RP) and to identify clinical biomarkers associated with rapid visual acuity decline based on baseline factors. Methods: This retrospective study included 59 eyes of 31 patients diagnosed with pericentral RP. Comprehensive ophthalmological examinations and genetic sequencing were conducted to assess the baseline characteristics. For biomarker analysis, eyes were categorized into two groups based on the annual rate of change in visual acuity. The clinical findings of the two groups were evaluated to identify the biomarkers associated with rapid loss of visual acuity. Results: Patients with pericentral RP in this study exhibited a mean best-corrected visual acuity of 0.17 ± 0.23 in logarithm of the minimum angle of resolution. The visual field test showed annular or semicircular scotoma with relatively preserved periphery and 27 eyes (45.8%) exhibited no macular complications in optical coherence tomography. Genetic analysis identified genes associated with previous typical and pericentral RP studies but also highlighted that many genetic causes of pericentral RP remain unidentified. Of the 55 eyes for which the rate of visual acuity change could be estimated, 18 exhibited an annual decline of ≥10%, whereas 37 showed an annual decline of <10%. Male sex and prolonged b-wave latency on dark-adapted 0.01 electroretinogram correlated with rapid visual acuity decline in the multivariate analysis. Conclusions South Korean patients with pericentral RP exhibited a milder phenotype compared to typical RP patients reported in previous studies. Genetic analysis revealed heterogeneity, with mutations in some genes commonly associated with milder forms of RP. Male sex and prolonged b-wave latency on dark-adapted 0.01 electroretinogram were significant biomarkers for predicting rapid visual acuity decline. Monitoring initial b-wave latency is important for predicting visual decline, particularly in male patients with pericentral RP.

Background and Objectives: Hearing loss significantly affects communication, psychosocial well-being, and quality of life. This study analyzes the National Health Insurance Service database to assess the trends and characteristics of hearing loss in South Korea from 2010 to 2020.Subjects and Method The database encompasses 97% of the Korean population, providing comprehensive data on medical history, prescriptions, and health examinations. The analysis used the World Health Organization’s ICD-10 definitions to categorize hearing loss types and examine their prevalence and incidence across various demographics over 11 years. Results: There was an overall annual increase of 4.62% in diagnosed cases of hearing loss, with the most significant rise among the elderly. The rate of increase accelerated from 3.32% between 2010 and 2014 to 6.49% between 2014 and 2020, corresponding with the improved hearing aid access facilitated by policy changes. Women showed a slightly higher increase than men. The data also indicated a consistent rise in abnormal hearing test results during health examinations, especially in older adults. Conclusion The study highlights an increasing trend in hearing loss diagnoses, driven by an aging population and enhanced detection facilitated by policy changes. These findings emphasize the need for continuous monitoring and targeted health policies to manage hearing loss effectively, offering valuable insights for global health management and policy development.

Background and Objectives: This study aims to analyze trends in hearing disability and the use of hearing rehabilitation devices (hearing aids and cochlear implants) in South Korea over the past 11 years (2010-2020) using data from the National Health Insurance Service (NHIS).Subjects and Method Data were extracted from the NHIS database, covering approximately 97% of the South Korean population. Patients diagnosed with hearing loss were classified using ICD-10 codes. The data were analyzed to determine trends in hearing disability, hearing aid prescriptions, and cochlear implant usage by age, gender, and types and causes of hearing loss. Results: The number of hearing disability patients increased from 170900 in 2010 to 362738 in 2020, with an annual growth rate of 7.95%. The highest increase was observed in the ≥60 age group, with an annual growth rate of 11.04%. Hearing aid prescriptions rose from 4966 in 2010 to 11974 in 2020, showing a 10.45% annual increase. Females showed a higher growth rate in both hearing disability and hearing aid prescriptions compared to males. Cochlear implant prescriptions also increased, particularly among older adults. Conclusion The study highlights a significant rise in hearing disability and the use of hearing aids and cochlear implants in South Korea, especially among the elderly. The findings underscore the importance of early diagnosis and intervention for hearing loss and the need for policy improvements to enhance accessibility and affordability of hearing rehabilitation services. Additional strategies are needed to ensure appropriate hearing rehabilitation for those not yet receiving adequate care.

Purpose: This study aimed to evaluate long-term treatment outcomes in patients with localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma treated with radiotherapy (RT). Materials and Methods: A total of 229 patients who received RT in 10 tertiary hospitals between 2010 and 2019 were included in this multicenter analysis. Response after RT was based on esophagogastroduodenoscopy after RT. Locoregional relapse-free survival (LRFS) and disease-free survival (DFS), and overall survival (OS) were evaluated. Results: After a median follow-up time of 93.2 months, 5-year LRFS, DFS, and OS rates were 92.8%, 90.4%, and 96.1%, respectively. LRFS, DFS, and OS rates at 10 years were 90.3%, 87.7%, and 92.8%, respectively. Of 229 patients, 228 patients (99.6%) achieved complete remission after RT. Five-year LRFS was significantly lower in patients with stage IIE than in those with stage IE (77.4% vs. 94.2%, p=0.047). Patients with age ≥ 60 had significantly lower LRFS than patients with age < 60 (89.3% vs. 95.1%, p=0.003). In the multivariate analysis, old age (≥ 60 years) was a poor prognostic factor for LRFS (hazard ratio, 3.72; confidence interval, 1.38 to 10.03; p=0.009). Grade 2 or higher gastritis was reported in 69 patients (30.1%). Secondary malignancies including gastric adenocarcinoma, malignant lymphoma, lung cancer, breast cancer, and prostate cancer were observed in 11 patients (4.8%) after RT. Conclusion Patients treated with RT for localized gastric MALT lymphoma showed favorable 10-year outcomes. Radiation therapy is an effective treatment without an increased risk of secondary cancer. The toxicity for RT to the stomach is not high.