2.The effects of Helicobacter pylori eradication and development of immune-mediated disorder in children: a nationwide population-based study in Korea
You Ie KIM ; Joon Sung KIM ; Sang Yong KIM ; Byung-Wook KIM
The Korean Journal of Internal Medicine 2026;41(1):85-94
Background/Aims:
Helicobacter pylori may protect against immune-mediated disorders such as inflammatory bowel disease (IBD) and asthma. This study evaluated whether eradication was associated with IBD and asthma in Korean children.
Methods:
Data were collected from the Korean National Health Insurance information on patients younger than 18 years and without a prior diagnosis of IBD or asthma from January 2007 to September 2020. Patients confirmed with H. pylori infection were divided into the eradication and non-eradication group. We compared the incidence of IBD and asthma in infected patients with an age, and sex-matched control group.
Results:
In total, 979,663 patients were selected based on the inclusion criteria and 2,779 patients were included based on the exclusion criteria. The occurrence of IBD in infected patients was statistically significant (p < 0.05) but there was no association of infection with asthma. There was no association with eradication and the development of IBD and asthma. The infected group had a shorter duration till diagnosis of IBD than the control group.
Conclusions
Our study found H. pylori infection to be associated with the development of IBD in children. However, eradication does not increase IBD and asthma in children.
4.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.
5.National Trends in Healthcare Quality in Korea: A Multidimensional Assessment Using OECD Health Care Quality Indicators (2008–2023)
Hyejin LEE ; Soo-Hee HWANG ; Sang-A CHO ; Hyemin JUNG ; Youngs CHANG ; Jieun YUN ; Sanghyun CHO ; Un-Na KIM ; Hye Yeon KOO ; Eun Byul CHO ; Do Hee KIM ; Jin Yong LEE
Journal of Preventive Medicine and Public Health 2026;59(3):225-238
Objectives:
Assessing healthcare quality at the national level is essential for evaluating health system performance and identifying areas requiring improvement. This study examined long-term trends in healthcare quality in Korea from 2008 to 2023 using internationally comparable indicators.
Methods:
We conducted a trend analysis of healthcare quality in Korea using the Organization for Economic Cooperation and Development (OECD) Health Care Quality and Outcomes framework and quality indicators. Indicators across multiple domains, including acute care, primary care, prescribing in primary care, mental healthcare, and patient experiences, were analyzed and compared with OECD averages.
Results:
Healthcare quality in Korea improved across several domains. Thirty-day mortality for acute myocardial infarction decreased from 14.2% in 2008 to 10.2% in 2023, while mortality for ischemic stroke declined from 8.7% to 5.5%. Avoidable hospitalizations decreased substantially, with hospitalizations for chronic obstructive pulmonary disease declining by 59.7%. The proportion of patients with diabetes receiving cholesterol-lowering treatment increased from 44.1% to 82.5%. However, the proportion of broad-spectrum antibiotic prescriptions remained substantially higher than the OECD average (40.3 vs. 15.5%). In mental healthcare, excess mortality ratios increased from 4.3 in 2010 to 4.9 in 2023 for schizophrenia and from 3.5 to 4.3 for bipolar disorder, while post-discharge suicide rates showed little improvement. Patient experience indicators related to patient-physician communication improved and approached OECD averages.
Conclusions
Healthcare quality in Korea improved substantially between 2008 and 2023, particularly in acute care outcomes and chronic disease management. However, persistent challenges remain in areas such as antibiotic use, polypharmacy, and mental healthcare. These findings provide internationally comparable evidence to inform future health policy and healthcare quality improvement efforts.
6.Individualized strategy of treatment for ruptured abdominal aortic aneurysm using causal inference model: a retrospective observational study
Youngki SOHN ; Youngje WOO ; Sangkyun MOK ; Eunju JANG ; Ki-Yoon MOON ; Sun Cheol PARK ; Sang Seob YUN ; Jang Yong KIM
Annals of Surgical Treatment and Research 2026;110(4):259-272
Purpose:
This study was performed to predict individualized treatment strategies in ruptured abdominal aortic aneurysm (rAAA) by estimating the survival benefit of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) based on anatomical and physiological features using a causal inference model.
Methods:
This retrospective study included 45 patients with de novo rAAA who underwent EVAR or OSR between 2012 and 2024. Thirty-three variables were analyzed. The model estimated individualized treatment effects (ITE) for 30-day survival.Model interpretability was assessed using Shapley Additive Explanations (SHAP) analysis. Five-fold cross-validation, receiver operating characteristic (ROC) analysis, and calibration plots were used for model evaluation. A clinical decision tree was developed to derive simplified decision rules.
Results:
The mean ITE was 0.22 ± 0.42, with 33% of patients classified as OSR-benefit candidates. SHAP analysis revealed that suprarenal angle, infrarenal angle, iliac anatomy, and proximal neck characteristics strongly influenced treatment effects. However, some predictors, such as low hemoglobin and systolic blood pressure favoring OSR, conflicted with clinical intuition. ROC analysis showed an area under the curve of 1.00, but calibration suggested overfitting due to a small sample size. Treatment-matched patients had a higher 30-day mortality rate than mismatched patients, suggesting potential bias or unmeasured confounding. The decision tree identified clinically relevant features but displayed structural inconsistencies and impractical cutoff values due to the limited sample size.
Conclusion
The X-learner model demonstrated the feasibility of individualized treatment prediction in rAAA but suffered from overfitting and limited generalizability. Validation with larger multicenter cohorts is necessary to confirm clinical applicability.
7.Surgical outcomes and prognostic factors in patients with retroperitoneal tumors: a single-center retrospective cohort study (2015–2024)
Mee Rae KIM ; Yubin LEE ; Yeojin BOO ; Jeong Ho SONG ; Sang-Yong SON ; Hoon HUR ; Sang-Uk HAN
Annals of Surgical Treatment and Research 2026;110(2):119-126
Purpose:
This study aimed to evaluate surgical outcomes, identify complications, and analyze recurrence in patients undergoing surgery for primary retroperitoneal tumors (RPTs), which pose significant therapeutic challenges.
Methods:
We retrospectively reviewed the medical records of 59 patients who underwent surgery for primary RPTs at Ajou University Hospital between January 2015 and December 2024. Patients were divided into a multivisceral resection (MVR) group (n = 25) and a non-MVR group (n = 34) to compare demographics, clinical characteristics, pathological findings, and postoperative outcomes.
Results:
Compared to the non-MVR group, the MVR group had a significantly higher rate of open surgery (96.0% vs.73.5%, P = 0.034), longer operative times (237.6 minutes vs. 188.8 minutes, P = 0.032), more frequent R2 resections (32.0% vs. 8.8%, P = 0.018), and longer hospital stays (13.1 days vs. 7.0 days, P = 0.007). Malignant tumors comprised 67.7% of cases, with sarcoma being the most common. Recurrence rates were highest in well-differentiated liposarcoma (50.0%) and dedifferentiated liposarcoma (22.2%). While univariate analysis showed MVR was associated with severe morbidity (Clavien-Dindo grade ≥III; odds ratio, 6.200; P = 0.029), this was not sustained as an independent predictor in multivariable analysis.
Conclusion
Although MVR was associated with severe complications in univariate analysis, it was not an independent predictor in multivariable analysis. This suggests the increased risk reflects overall surgical complexity. Therefore, MVR should be pursued when oncologically necessary, as it presents an acceptable morbidity profile.
8.Progesterone receptor expression and its prognostic role in hormone receptor-positive/human epidermal growth factor receptor 2-positive breast cancer: a retrospective cohort study
Ji Hye KIM ; Yeryung KIM ; Jai Hyun CHUNG ; Yong Yeup KIM ; Woo Young KIM ; Jae Bok LEE ; Sang Uk WOO
Annals of Surgical Treatment and Research 2026;110(2):112-118
Purpose:
While progesterone receptor (PR) negativity in luminal-type breast cancer is generally associated with worse oncologic outcomes, its prognostic role in estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-positive breast cancer remains underexplored. This study aimed to evaluate the prognostic significance of PR expression in ER-positive, HER2-positive breast cancer.
Methods:
A retrospective analysis was conducted on patients diagnosed with ER-positive, HER2-positive breast cancer who underwent primary surgery at Korea University Guro Hospital between January 2009 and December 2019. Patients were grouped by PR expression as negative/low (Allred score, 0–6) or strongly positive (Allred score,7 or 8). Prognostic outcomes, including disease-free survival (DFS), distant recurrence-free survival (DRFS), and breast cancer-specific survival (BCSS) were analyzed.
Results:
A total of 223 patients were included. Patients in the negative/low PR group were older compared to the strongly positive PR group. The negative/low PR group showed significantly worse DFS (P = 0.005) and DRFS (P = 0.014) but showed no significant difference in BCSS (P = 0.153). On multivariate analysis, negative or low PR expressions were linked to inferior DFS (hazard ratio [HR], 3.10; 95% confidence interval [CI], 1.34–7.16; P = 0.008) and DRFS (HR, 9.55; 95% CI, 1.22– 74.77; P = 0.032).
Conclusion
In ER-positive, HER2-positive breast cancer, negative or weak PR expression was associated with inferior DFS and DRFS compared to strong PR expression. These findings highlight the potential prognostic value of PR status in this group, underscoring its relevance in guiding treatment and follow-up strategies for more individualized patient care.
9.A unified framework for postoperative complications after gastrectomy for gastric cancer: insights from the Korean Quality Improvement Platform in Surgery program
Jeong Ho SONG ; Chang Seok KO ; Han Hong LEE ; Hong Man YOON ; Hyoung-Il KIM ; In Gyu KWON ; Ji Yeon PARK ; Ji Yeong AN ; Jong Won KIM ; Mi Ran JUNG ; Sang-Il LEE ; Seong Ho KONG ; Sun-Hwi HWANG ; Yun-Suhk SUH ; Sang-Yong SON ; Sang-Uk HAN
Annals of Surgical Treatment and Research 2026;110(5):290-298
Purpose:
Postoperative complications following gastric cancer surgery significantly impact patient outcomes, yet standardized definitions for these events have not been consistently applied across institutions in Korea. This study aimed to develop a consensus-based, standardized complication classification system specific to gastrectomy for gastric cancer as part of the Korean Quality Improvement Platform in Surgery (K-QIPS) initiative.
Methods:
As part of K-QIPS, a dedicated task force team (TFT) was formed with surgical experts from fourteen high-volume hospitals across Korea. The TFT conducted ten formal meetings to review existing literature and international guidelines, and incorporated findings from randomized controlled trials. The final complication list was developed through expert consensus and structured into a standardized framework. A Data Entry Manual was created to support consistent data collection by surgical clinical reviewers.
Results:
The TFT defined specific postoperative complications following gastrectomy for gastric cancer, including anastomotic leakage, duodenal stump leakage, pancreatic fistula, intra-abdominal and luminal bleeding, delayed gastric emptying, and internal hernia. Notably, internal hernia was described in standardized form for the first time. General complications were developed first and overlapped in part with the gastric cancer-specific list. The task force also produced a Data Entry Manual that provides practical instructions to ensure consistency and accuracy in complication reporting.
Conclusion
This nationwide consensus initiative established the first standardized complication classification system for gastric cancer surgery in Korea. The proposed definitions and data entry system are expected to improve complication reporting, enable multicenter research, support surgical quality benchmarking, and ultimately enhance patient outcomes.
10.Efficacy and safety of metabolic bariatric surgery in patients aged ≥55 years: a multicenter retrospective cohort study in East Asians
Yoontaek LEE ; Han Hong LEE ; Ho Seok SEO ; Chang Min LEE ; Sang-Yong SON ; Young Suk PARK ; Sang Hyun KIM
Annals of Surgical Treatment and Research 2026;110(5):281-289
Purpose:
Metabolic bariatric surgery (MBS) efficacy and safety is established for older patients, but East Asian data are limited. This study aimed to evaluate the safety and efficacy of MBS by comparing older (≥55 years) and younger (<55 years) East Asian patients with obesity.
Methods:
This multicenter, retrospective review included 410 patients undergoing MBS from January to December 2019.Patients were stratified into the older group (OG, age ≥55 years; n = 39) and the younger group (YG, age <55 years; n = 371). We compared surgical safety, weight parameters, and comorbidity resolution rates.
Results:
The OG had lower mean body weight (97.9 ± 16.4 kg vs. 113.2 ± 23.1 kg, P < 0.001) but more comorbidities and lower average ABCD score for type 2 diabetes mellitus (T2DM) remission. Postoperative complication rate (12.8% vs. 7.5%, P = 0.400) and postoperative hospital stay (4.1 ± 1.8 days vs. 4.0 ± 8.9 days, P = 0.773) showed no significant differences.At 12 months, the percentage of total weight loss was significantly lower in the OG (23.7 ± 6.9% vs. 27.8 ± 8.4%, P = 0.014).Remission rates for T2DM (47.6% vs. 80.5%, P < 0.001), hypertension (34.6% vs. 57.5%, P = 0.073), and dyslipidemia (12.5% vs. 44.4%, P = 0.012) were also lower in the OG, yet still demonstrated clinically meaningful metabolic improvement.
Conclusion
MBS is a safe and effective treatment for older East Asians with obesity, offering substantial comorbidity resolution despite achieving a lower weight loss compared to the younger patients.

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