Chia-Hung Tu

Performance of the immunochemical fecal occult blood test in predicting lesions in the lower gastrointestinal tract

Background: Previous studies have suggested that the immunochemical fecal occult blood test has superior specificity for detecting bleeding in the lower gastrointestinal tract even if bleeding occurs in the upper tract. We conducted a large population-based study involving asymptomatic adults in Taiwan, a population with prevalent upper gastrointestinal lesions, to confirm this claim. Methods: We conducted a prospective cohort study involving asymptomatic people aged 18 years or more in Taiwan recruited to undergo an immunochemical fecal occult blood test, colonoscopy and esophagogastroduodenoscopy between August 2007 and July 2009. We compared the prevalence of lesions in the lower and upper gastrointestinal tracts between patients with positive and negative fecal test results. We also identified risk factors associated with a false-positive fecal test result. Results: Of the 2796 participants, 397 (14.2%) had a positive fecal test result. The sensitivity of the test for predicting lesions in the lower gastrointestinal tract was 24.3%, the specificity 89.0%, the positive predictive value 41.3%, the negative predictive value 78.7%, the positive likelihood ratio 2.22, the negative likelihood ratio 0.85 and the accuracy 73.4%. The prevalence of lesions in the lower gastrointestinal tract was higher among those with a positive fecal test result than among those with a negative result (41.3% v. 21.3%, p < 0.001). The prevalence of lesions in the upper gastrointestinal tract did not differ significantly between the two groups (20.7% v. 17.5%, p = 0.12). Almost all of the participants found to have colon cancer (27/28, 96.4%) had a positive fecal test result; in contrast, none of the three found to have esophageal or gastric cancer had a positive fecal test result (p < 0.001). Among those with a negative finding on colonoscopy, the risk factors associated with a false-positive fecal test result were use of antiplatelet drugs (adjusted odds ratio [OR] 2.46, 95% confidence interval [CI] 1.21–4.98) and a low hemoglobin concentration (adjusted OR 2.65, 95% CI 1.62–4.33). Interpretation: The immunochemical fecal occult blood test was specific for predicting lesions in the lower gastrointestinal tract. However, the test did not adequately predict lesions in the upper gastrointestinal tract.

The Application of Prague C and M Criteria in the Diagnosis of Barrett's Esophagus in an Ethnic Chinese Population

OBJECTIVES:To investigate the prevalence of endoscopically suspected esophageal metaplasia (ESEM) in an ethnic Chinese population by endoscopic and pathologic evaluation and to assess the utility of Prague C and M criteria.METHODS:Consecutive patients who received esophagogastroduodenoscopy either as a part of therapy for various upper abdominal symptoms or as an annual health check-up were evaluated for the existence of ESEM and Barrett’s esophagus (BE). Biopsy with standardized random four pieces every 2 cm from the four quarters of esophagus with ESEM lesion was performed. BE was defined by histological verification of specialized intestinal metaplasia and gastric metaplasia and was categorized according to the Prague C and M criteria.RESULTS:A total of 5,179 subjects were screened from Jan. 2007 to Dec. 2007. This study enrolled 4,797, including 3,386 for referral endoscopy and 1,411 for screening endoscopy. Prevalence of BE among the referral endoscopy, screening endoscopy, and overall was 1.06%, 0.35%, and 0.85%, respectively. A total of 41 subjects with BE were detected among 93 ESEM subjects. Short segment BE (75.6%, n=31) was more prevalent than long segment BE (24.4%, n=10). The proportions of BE from subjects with ESEM by Prague C and M criteria were C≤1M1 38.9% (19/50), C≤1M2 40% (12/30), and C×M≥3 76.9% (10/13).CONCLUSIONS:On the basis of the standardized protocol with random four-quadrate endoscopic biopsy, we have demonstrated the utility of Prague C and M criteria to characterize the BE in an ethnic Chinese population.

Patients with functional heartburn are more likely to report retrosternal discomfort during wireless pH monitoring

BACKGROUND Although the wireless Bravo pH system is effective, some patients experience retrosternal sensations possibly caused by esophageal sensitivity that may complicate clinical application. METHODS Ambulatory pH of 40 consecutive patients with GERD who had erosive esophagitis or nonerosive reflux disease, were monitored for 2 days with the Bravo system. Results were stratified and compared on the basis of self-awareness of the intraesophageal capsule. RESULTS Pathologic acid reflux was diagnosed in 20 patients and normal reflux was diagnosed in 20 patients. Seventeen patients (42.5%) reported retrosternal discomfort, and 12 of them (70.6%) had normal reflux. Patients with retrosternal discomfort were less likely to have moderate endoscopic esophagitis, i.e., Los Angeles classification grades B, C, and D endoscopic esophagitis (p = 0.006), and were less likely to have significantly elevated esophageal acid exposure (p = 0.0036) than those who did not perceive the discomfort. Reported discomfort was not associated with age, gender, or the presence of endoscopic esophagitis. CONCLUSIONS The negative correlation between Bravo-capsule-induced retrosternal discomfort and esophageal-acid exposure indicates modified mechanical afferent nerve function after long-term acid stimulation. Capsule-induced retrosternal discomfort in the presence of normal acid exposure suggests functional heartburn.

Association of Diabetes and HbA1c Levels With Gastrointestinal Manifestations

OBJECTIVE To determine the prevalence of gastrointestinal (GI) manifestations associated with diabetes mellitus (DM) in a Taiwanese population undergoing bidirectional endoscopies. RESEARCH DESIGN AND METHODS Subjects voluntarily undergoing upper endoscopy/colonoscopy as part of a medical examination at the National Taiwan University Hospital were recruited during 2009. Diagnosis of DM included past history of DM, fasting plasma glucose ≥126 mg/dL, or glycated hemoglobin (HbA1c) ≥6.5%. Comparisons were made between diabetic and nondiabetic subjects, subjects with lower and higher HbA1c levels, and diabetic subjects with and without complications, respectively, for their GI symptoms, noninvasive GI testing results, and endoscopic findings. RESULTS Among 7,770 study subjects, 722 (9.3%) were diagnosed with DM. The overall prevalence of GI symptoms was lower in DM subjects (30.3 vs. 35.4%, P = 0.006). In contrast, the prevalence of erosive esophagitis (34.3 vs. 28.6%, P = 0.002), Barretts esophagus (0.6 vs. 0.1%, P = 0.001), peptic ulcer disease (14.8 vs. 8.5%, P < 0.001), gastric neoplasms (1.8 vs. 0.7%, P = 0.003), and colonic neoplasms (26.6 vs. 16.5%, P < 0.001) was higher in diabetic subjects. Diagnostic accuracy of immunochemical fecal occult blood test for colonic neoplasms was significantly decreased in DM (70.7 vs. 81.7%, P < 0.001). Higher HbA1c levels were associated with a decrease of GI symptoms and an increase of endoscopic abnormalities. Diabetic subjects with complications had a higher prevalence of colonic neoplasms (39.2 vs. 24.5%, P = 0.002) than those without. CONCLUSIONS DM and higher levels of HbA1c were associated with lower prevalence of GI symptoms but higher prevalence of endoscopic abnormalities.

Nonalcoholic Fatty Liver Disease Is Associated With QT Prolongation in the General Population

Background Nonalcoholic fatty liver disease (NAFLD) is independently associated with QT prolongation among patients with diabetes. It has not yet been determined whether this association remains valid in the general population. We designed an observational study to explore this association. Methods and Results We conducted a cross-sectional analysis of 31 116 consecutive participants in our health management program. Heart rate–corrected QT (QTc) interval was derived from 12-lead electrocardiography and by Bazett’s formula. NAFLD was diagnosed by abdominal ultrasonography and classified as none, mild, moderate, or severe, according to the ultrasonographic criteria. A multivariable linear regression model was fitted for the association between QTc interval and potential predictors (including demographic, anthropometric, biochemical factors, and comorbidities). Multivariable logistic regression analyses were fitted to assess the association between the severity of NAFLD and QTc prolongation, with the adjustment of significant predictors derived from multivariable linear regression. The mean QTc interval was 421.3 ms (SD 45.4 ms). In the multivariable linear regression analyses, mild, moderate, and severe NAFLD were associated with increases of 2.55, 6.59, and 12.13 ms, respectively, in QTc interval compared with no NAFLD (all P<0.001). In the multivariable logistic regression analyses, mild, moderate, and severe NAFLD were associated with an increased risk for QTc prolongation, with odds ratios of 1.11 (95% CI: 1.01 to 1.21, P<0.05), 1.61 (95% CI: 1.36 to 1.9, P<0.001), and 1.31 (95% CI: 1.16 to 2.24, P<0.01), respectively, in women, and 1.11 (95% CI: 1.01 to 1.21, P<0.05), 1.39 (95% CI: 1.22 to 1.59, P<0.001), and 1.87 (95% CI: 1.16 to 2.24, P<0.001), respectively, in men, after adjusting for predictors known to be associated with the QTc interval. The association remained significant among subgroups with or without diabetes. Conclusions The severity of NAFLD was associated with a higher risk for QTc prolongation in the general population with and without diabetes.

Association of Esophageal Inflammation, Obesity and Gastroesophageal Reflux Disease: From FDG PET/CT Perspective

Objective Gastroesophageal reflux disease (GERD) is associated with bothersome symptoms and neoplastic progression into Barretts esophagus and esophageal adenocarcinoma. We aim to determine the correlation between GERD, esophageal inflammation and obesity with 18F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). Methods We studied 458 subjects who underwent a comprehensive health check-up, which included an upper gastrointestinal endoscopy, FDG PET/CT and complete anthropometric measures. GERD symptoms were evaluated with Reflux Disease Questionnaire. Endoscopically erosive esophagitis was scored using the Los Angeles classification system. Inflammatory activity, represented by standardized uptake values (SUVmax) of FDG at pre-determined locations of esophagus, stomach and duodenum, were compared. Association between erosive esophagitis, FDG activity and anthropometric evaluation, including body mass index (BMI), waist circumference, visceral and subcutaneous adipose tissue volumes were analyzed. Results Subjects with erosive esophagitis (n = 178, 38.9%) had significantly higher SUVmax at middle esophagus (2.69±0.74 vs. 2.41±0.57, P<.001) and esophagogastric junction (3.10±0.89 vs. 2.38±0.57, P<.001), marginally higher at upper esophageal sphincter (2.29±0.42 vs. 2.21±0.48, P = .062), but not in stomach or duodenum. The severity of erosive esophagitis correlated with SUVmax and subjects with Barretts esophagus had the highest SUVmax at middle esophagus and esophagogastric junction. Heartburn positively correlated with higher SUVmax at middle oesophagus (r = .262, P = .003). Using multivariate regression analyses, age (P = .027), total cholesterol level (P = .003), alcohol drinking (P = .03), subcutaneous adipose tissue (P<.001), BMI (P<.001) and waist circumference (P<.001) were independently associated with higher SUVmax at respective esophageal locations. Conclusions Esophageal inflammation demonstrated by FDG PET/CT correlates with endoscopic findings and symptomatology of GERD. Obesity markers, both visceral and general, are independent determinants of esophageal inflammation.

Performance of a one-step fecal sample-based test for diagnosis of Helicobacter pylori infection in primary care and mass screening settings

BACKGROUND/PURPOSE An alternative screening test is needed to efficiently eradicate Helicobacter pylori from a population with prevalent upper gastrointestinal lesions. We evaluated the performance of a new one-step fecal test for H. pylori for diagnosis of H. pylori infection in Taiwan. METHODS We developed a fecal test to detect H. pylori based on the immunochronomatographic assay and a mixture of monoclonal antibodies. We first recruited symptomatic patients from the primary care setting to evaluate fecal test performance using a reference standard consisting of (13)C urea breath test, rapid urease test, and histology. We also compared the performance of the fecal test with that of others. Next, we recruited asymptomatic participants from the mass screening setting to evaluate population attendance for the fecal test and compared its performance with that of (13)C urea breath test. RESULTS In the primary care setting, 117 patients were recruited; H. pylori infection was confirmed in 58 (49.6%). Fecal test sensitivity, specificity, positive and negative predictive values, and accuracy were 88.0% [95% confidence interval (CI): 79.6-96.4%], 100%, 100%, 89.4% (95% CI, 82.0-96.8%), and 94% (95% CI, 89.7-98.3%), respectively. Fecal test specificity and positive predictive value were significantly higher than those of the serological test, whereas the sensitivity and negative predictive value were lower than those of the (13)C urea breath test (p < 0.05). In the mass screening setting, 2720 of 3520 invited individuals participated (77.3%; 95% CI, 76-78.7%); 649 (23.9%) showed positive results. Concordance rate and kappa statistic between the fecal test and (13)C urea breath test were 91.7% (563/614; 95% CI, 89.9-94.1%) and 0.78 (95% CI, 0.73-0.84), respectively. CONCLUSION Given the acceptable sensitivity, excellent specificity, and high participation rate to screening, the one-step H. pylori stool antigen test is feasible for wide application in the community.

An endoscopic training model to improve accuracy of colonic polyp size measurement

PurposeMost studies of colonic polyps rely on visual estimation when regarding polyp size; however, the reliability of a visual estimate is questionable. Our study aims to develop a training model to improve the accuracy of size estimation of colonic polyps in vivo.MethodsColon polyps were recorded on 160 video clips during colonoscopy. The size of each polyp was estimated by visual inspection and subsequently measured with a flexible linear measuring probe. The study included a pretest, an intervention, and a posttest. The pretest included 160 video clips, which comprised the visual-estimation portion of the study. The intervention was an educational model consisting of 30 video clips which included a visual-estimation section and a linear-measuring-probe section, designed to help the endoscopists to compare their visual estimate of size with the measured size of the polyps. The posttest included the 160 video clips used in the pretest, presented in random order. Intraobserver agreement and diagnostic accuracy were compared before and after the training session.ResultsEight beginners and four experienced colonoscopists were enrolled. The overall kappa (κ) values of intraobserver agreement for pretest and posttest were 0.74 and 0.85 for beginner group as well as 0.83 and 0.88 for experienced group, respectively. The overall diagnostic accuracy improved from 0.52 to 0.78 for beginner group and 0.71 to 0.87 for experienced group (P < 0.05) after education with the training model.ConclusionsThis training model could help endoscopists improve the accuracy of measurement of polyps on colonoscopy in a short period. The durability of learning effect needs further investigation.

Myocardial ischemia during endoscopic retrograde cholangiopancreatography: an overlooked issue with significant clinical impact

Background and Aim:  The occurrence of peri‐procedural myocardial ischemia with endoscopic retrograde cholangiopancreatography (ERCP) has been documented, but its significance remains controversial. This study aimed to investigate the incidence and risk factors of myocardial ischemia during ERCP procedures and to analyze the potential association between myocardial ischemia and post‐ERCP complications.

Normative values and factors affecting water-perfused esophageal high-resolution impedance manometry for a Chinese population

Combined esophageal high‐resolution impedance manometry (HRIM) measures multiple pressures and bolus transit simultaneously, facilitating detailed assessment of esophageal motility. Currently, normative values for water‐perfused HRIM systems for Chinese populations are lacking.