Ji Yong Ahn

Prof. Dr. Ji Yong Ahn


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 June 2018 in BMC Gastroenterology
Verified
Journal Article
Open access
PDF file
GPGyu Young Pih
Gyu Young Pih
HNHee Kyong Na
Hee Kyong Na
JAJi Yong Ahn
Ji Yong Ahn
KJKee Wook Jung
Kee Wook Jung
AKASAN MEDICAL CENTER Kim
ASAN MEDICAL CENTER Kim
HJHwoon-yong Jung
Hwoon-yong Jung
Percutaneous endoscopic gastrostomy (PEG) is a relatively safe procedure; however, acute and chronic complications of PEG have been reported. We aimed to determine risk factors associated with complications and 30-day mortality after PEG, based on 11 years of experience at a single tertiary hospital. In total, 401 patients who underwent first PEG insertion at the Asan Medical Center, Seoul, Korea, between January 2005 and December 2015 were eligible. Medical records were retrospectively reviewed to determine clinical characteristics and outcomes of 139 and 262 patients who underwent pull-type and introducer-type PEG, respectively. The median age of the overall population was 68 years, and the median body mass index was 19.5 kg/m2. Acute and chronic complications developed in 96 (23.9%) and 105 (26.2%) patients. Acute ileus and chronic tube obstruction were significantly more frequent in the introducer-type PEG group (p = 0.033 and 0.001, respectively). The 30-day mortality rate was 5.0% (median survival: 10.5 days). Multivariate analysis revealed that underlying malignancy was a predictor of acute complications; age ≥ 70 years and diabetes mellitus were predictors of chronic complications. The median follow-up was 354 days. Neurologic disease and malignancy were the most common indications for PEG. Neurologic diseases were classified into two groups: stroke and the other neurologic disease group (including dementia, Parkinson’s disease, neuromuscular disease, and hypoxic brain damage). Multivariate analysis showed that 30-day mortality was significantly lower in the other neurologic disease group and higher in patients with platelet count < 100,000/μL, and C-reactive protein (CRP) ≥ 5 mg/dL. PEG is a relatively safe and feasible procedure, but it was associated with significantly higher early mortality rate in patients with platelet count < 100,000/μL or CPR≥5mg/dL, and lower early mortality rate in neurologic disease group including dementia, Parkinson's disase, neuromuscular disease, and hypoxic brain damage. In addition, acute complications in patients with underlying malignancy, and chronic complications in patients aged ≥70 and those with diabetes mellitus should be considered during and after PEG.

1 January 2014 in Journal of Korean Medical Science
Verified
Journal Article
Open access
EGEun Jeong Gong
Eun Jeong Gong
SYSung-Cheol Yun
Sung-Cheol Yun
HJHwoon-yong Jung
Hwoon-yong Jung
HLHyun Lim
Hyun Lim
KCKwi-Sook Choi
Kwi-Sook Choi
JKJin-Ho Kim
Jin-Ho Kim
Proton pump inhibitor (PPI)-based triple therapy consisting of PPI, amoxicillin, and clarithromycin, is the recommended first-line treatment for Helicobacter pylori infection. However, the eradication rate of triple therapy has declined over the past few decades. We analyzed the eradication rate and adverse events of triple therapy to evaluate current practices in Korea. A comprehensive literature search was performed up to August 2013 of 104 relevant studies comprising 42,124 patients. The overall eradication rate was 74.6% (95% confidence interval [CI], 72.1%-77.2%) by intention-to-treat analysis and 82.0% (95% CI, 80.8%-83.2%) by per-protocol analysis. The eradication rate decreased significantly from 1998 to 2013 (P < 0.001 for both intention-to-treat and per-protocol analyses). Adverse events were reported in 41 studies with 8,018 subjects with an overall incidence rate of 20.4% (95% CI, 19.6%-21.3%). The available data suggest that the effectiveness of standard triple therapy for H. pylori eradication has decreased to an unacceptable level. A novel therapeutic strategy is warranted to improve the effectiveness of first-line treatment for H. pylori infection in Korea.

15 April 2021 in Cancer Research and Treatment
Verified
Journal Article
Open access
PDF file
GPGyu Young Pih
Gyu Young Pih
EGEun Jeong Gong
Eun Jeong Gong
JCJi Young Choi
Ji Young Choi
MKMin-Ju Kim
Min-Ju Kim
JAJi Yong Ahn
Ji Yong Ahn
HJHwoon-Yong Jung
Hwoon-Yong Jung
Purpose The association of serum lipids with gastric cancer is controversial. We clarified the role of serum lipids in the development, progression, and prognosis of gastric cancer.Materials and Methods In total, 412 patients diagnosed with gastric cancer were prospectively recruited, and 2,934 control subjects who underwent screening endoscopy were enrolled from December 2013 to March 2017 to conduct a case-control study in a tertiary center. Serum lipid profiles, including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), apolipoprotein A-I (apoA-I), and apolipoprotein B, and clinicopathologic characteristics were analyzed.Results The gastric cancer group showed significantly lower HDL-C, higher LDL-C, and lower apoA-I level than the control group. In multivariate analysis, old age (odds ratio [OR], 1.051; p < 0.001), smoking (OR, 1.337; p < 0.001), a family history of gastric cancer (OR, 2.038; p < 0.001), Helicobacter pylori seropositivity (OR, 4.240; p < 0.001), lower HDL-C (OR, 0.712; p=0.020), and higher LDL-C (p=0.002) were significant risk factors for gastric cancer. Lower HDL-C and higher LDL-C remained significant after adjustments for covariates, including age and sex. In a subgroup analysis of the gastric cancer group, lower TG levels were associated with undifferentiated histology. No serum lipids were associated with overall survival.Conclusion Lower HDL-C and higher LDL-C were associated with the risk of gastric cancer, even after adjusting for age, sex, and other factors. In the gastric cancer group, undifferentiated histology was associated with lower TG levels.

15 November 2020 in Gut and Liver
Verified
Journal Article
Open access
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MJMoon Kyung Joo
Moon Kyung Joo
CPChan Hyuk Park
Chan Hyuk Park
JKJoon Sung Kim
Joon Sung Kim
JPJae Myung Park
Jae Myung Park
JAJi Yong Ahn
Ji Yong Ahn
KRKorean College of Helicobacter Upper Gastrointestinal Research
Korean College of Helicobacter Upper Gastrointestinal Research
Moon Kyung Joo, Chan Hyuk Park, Joon Sung Kim, Jae Myung Park, Ji Yong Ahn, Bong Eun Lee, Jeong Hoon Lee, Hyo-Joon Yang, Yu Kyung Cho, Chang Seok Bang, Beom Jin Kim, Hye-Kyung Jung, Byung-Wook Kim, and Yong Chan Lee, Korean College of Helicobacter and Upper Gastrointestinal Research. Gut and Liver 2020;14:707-26. https://doi.org/10.5009/gnl20246

27 November 2013 in Digestive Diseases and Sciences
Verified
Journal Article
Closed access
PDF file
JAJi Yong Ahn
Ji Yong Ahn
KLKyung Hun Lee
Kyung Hun Lee
CCChang Hwan Choi
Chang Hwan Choi
JKJu Wan Kim
Ju Wan Kim
HLHYUN WOONG LEE
HYUN WOONG LEE
SCSae Kyung Chang
Sae Kyung Chang

15 April 2021 in Journal of Medical Internet Research
Verified
Journal Article
Open access
Chang Seok BangChang Seok Bang
Chang Seok Bang
JAJi Yong Ahn
Ji Yong Ahn
JKJie-Hyun Kim
Jie-Hyun Kim
YKYoung-Il Kim
Young-Il Kim
ICIl Ju Choi
Il Ju Choi
WSWoon Geon Shin
Woon Geon Shin
Background: Undifferentiated type of early gastric cancer (U-EGC) is included among the expanded indications of endoscopic submucosal dissection (ESD); however, the rate of curative resection remains unsatisfactory. Endoscopists predict the probability of curative resection by considering the size and shape of the lesion and whether ulcers are present or not. The location of the lesion, indicating the likely technical difficulty, is also considered. Objective: The aim of this study was to establish machine learning (ML) models to better predict the possibility of curative resection in U-EGC prior to ESD. Methods: A nationwide cohort of 2703 U-EGCs treated by ESD or surgery were adopted for the training and internal validation cohorts. Separately, an independent data set of the Korean ESD registry (n=275) and an Asan medical center data set (n=127) treated by ESD were chosen for external validation. Eighteen ML classifiers were selected to establish prediction models of curative resection with the following variables: age; sex; location, size, and shape of the lesion; and whether ulcers were present or not. Results: Among the 18 models, the extreme gradient boosting classifier showed the best performance (internal validation accuracy 93.4%, 95% CI 90.4%-96.4%; precision 92.6%, 95% CI 89.5%-95.7%; recall 99.0%, 95% CI 97.8%-99.9%; and F1 score 95.7%, 95% CI 93.3%-98.1%). Attempts at external validation showed substantial accuracy (first external validation 81.5%, 95% CI 76.9%-86.1% and second external validation 89.8%, 95% CI 84.5%-95.1%). Lesion size was the most important feature in each explainable artificial intelligence analysis. Conclusions: We established an ML model capable of accurately predicting the curative resection of U-EGC before ESD by considering the morphological and ecological characteristics of the lesions.