Carbon urea breath test is not as accurate as endoscopy to detect Helicobacter pylori after gastrectomy

Urea breath test for Helicobacter pylori infection in adult dyspeptic patients: A meta-analysis of diagnostic test accuracy

BACKGROUND

Helicobacter pylori (H. pylori) infection has been well-established as a significant risk factor for several gastrointestinal disorders. The urea breath test (UBT) has emerged as a leading non-invasive method for detecting H. pylori. Despite numerous studies confirming its substantial accuracy, the reliability of UBT results is often compromised by inherent limitations. These findings underscore the need for a rigorous statistical synthesis to clarify and reconcile the diagnostic accuracy of the UBT for the diagnosis of H. pylori infection.

AIM

To determine and compare the diagnostic accuracy of 13C-UBT and 14C-UBT for H. pylori infection in adult patients with dyspepsia.

METHODS

We conducted an independent search of the PubMed/MEDLINE, EMBASE, and Cochrane Central databases until April 2022. Our search included diagnostic accuracy studies that evaluated at least one of the index tests (13C-UBT or 14C-UBT) against a reference standard. We used the QUADAS-2 tool to assess the methodological quality of the studies. We utilized the bivariate random-effects model to calculate sensitivity, specificity, positive and negative test likelihood ratios (LR+ and LR-), as well as the diagnostic odds ratio (DOR), and their 95% confidence intervals. We conducted subgroup analyses based on urea dosing, time after urea administration, and assessment technique. To investigate a possible threshold effect, we conducted Spearman correlation analysis, and we generated summary receiver operating characteristic (SROC) curves to assess heterogeneity. Finally, we visually inspected a funnel plot and used Egger's test to evaluate publication bias.

RESULTS

The titles and abstracts of 4621 studies were screened; 79 articles were retrieved and selected for full-text reading. Finally, 60 studies were included in the diagnostic test accuracy meta-analysis. Our analysis demonstrates superior diagnostic accuracy of 13C-UBT over 14C-UBT, indicated by higher sensitivity (96.60% vs 96.15%), specificity (96.93% vs 89.84%), likelihood ratios (LR+ 22.00 vs 10.10; LR- 0.05 vs 0.06), and area under the curve (AUC; 0.979 vs 0.968). Notably, 13C-UBT's DOR (586.47) significantly outperforms 14C-UBT (DOR 226.50), making it the preferred diagnostic tool for dyspeptic individuals with H. pylori infection. Correlation analysis revealed no threshold effect (13C-UBT: r = 0.48; 14C-UBT: r = -0.01), and SROC curves showed consistent accuracy. Both 13C-UBT and 14C-UBT showed high AUC values (13C-UBT 0.979; 14C-UBT 0.968) near 1.00, reinforcing their excellent accuracy and endorsing both as reliable diagnostic tools in clinical practice.

CONCLUSION

In summary, our study has demonstrated that 13C-UBT has been found to outperform the 14C-UBT, making it the preferred diagnostic approach. Additionally, our results emphasize the significance of carefully considering urea dosage, assessment timing, and measurement techniques for both tests to enhance diagnostic precision. Nevertheless, it is crucial for researchers and clinicians to evaluate the strengths and limitations of our findings before implementing them in practice.

Declining trends of prevalence of Helicobacter pylori infection and incidence of gastric cancer in Taiwan: An updated cross-sectional survey and meta-analysis

BACKGROUND

We aimed to assess the latest prevalence and secular trend of Helicobacter pylori infection and its association with the incidence and mortality of gastric cancer in Taiwan.

MATERIALS AND METHODS

Adults naive to H. pylori eradication received ¹³ C-urea breath test (¹³ C-UBT), H. pylori stool antigen test, and serology test during 2019-2020 in this prospective screening program. Children and adolescent aged between 7 and 19 years received ¹³ C-UBT for H. pylori screening. We also conducted a systematic review and meta-analysis to assess the secular trend of prevalence of H. pylori from 1990 to 2020 in Taiwan. The secular trends of age-standardized incidence and mortality of gastric cancer were obtained from the Taiwan Cancer Registry.

RESULTS

A total of 1494 participants were enrolled, including 294 children or adolescents and 1200 adults. The overall prevalence of active H. pylori infection by ¹³ C-UBT was 26.6% (397/1494), which was 30.8% in adults and 9.5% in adolescents/children. The age-standardized prevalence of active H. pylori infection was 32.3% in adults after adjustment of the population structure in Taiwan. Of the 29 studies including 38,597 subjects eligible for the meta-analysis, the pooled prevalence of H. pylori infection decreased from 63.8% (95% CI: 55.9%-71%) in 1990-2000 to 28.2% (95% CI:21.8%-35.6%) in 2016-2020. The age-standardized incidence and mortality of gastric cancer have also declined from 15.2 to 10.75 per 100,000, respectively, in 1999 to 9.29 and 5.4 per 100,000, respectively, in 2019.

CONCLUSIONS

The prevalence of H. pylori infection has declined in Taiwan, which correlates with the declining trends of age-standardized incidence and mortality of gastric cancer in Taiwan.

13C-Urea Breath Test for the Diagnosis of H. pylori Infection in Patients after Partial Gastrectomy: A Systematic Review and Meta-Analysis

BACKGROUND

The ¹³C-urea breath test (¹³C-UBT) is a kind of safe, noninvasive, and reliable measure for Helicobacter pylori (H. pylori) infection diagnosis in patients with complete stomach. Nevertheless, the test has not indicated fully precision in people who have had a gastrectomy. So, we made the use of a systematic review of plentiful published resources and research and meta-analysis. There are prominent research achievements regarding of utilizing ¹³C-UBT for H. pylori infection patients diagnosis with the residual stomach.

METHOD

We searched publications available on Cochrane, PubMed, and Embase databases, and on the web of science. The last search was performed in May 2021. The basis model for this meta-analysis was fixed-effect through Metadisc Beta 1.4 software (Universidad Complutense, Madrid, Spain). When measuring the precision of ¹³C-urea breath test, we utilized the ratio analysis such as Ratio of diagnostic odds ratio (DOR) and its corresponding 95% confidence interval (95%CI).

RESULTS

Ten associated researches were analyzed with a total of 1065 patients. In general, the sensitivity of included studies ranged from 0.40 to 1.00 (I² = 81.2%), whereas the specificity ranged from 0.59 to 1.00 (I² = 90.1%). The pooled sensitivity, specificity were 0.83 (95% CI, 0.79-0.86; P < 0.001), 0.79 (95% CI, 0.76-0.83; P < 0.001) respectively. The accuracy ranged from 71 to 99. The positive predictive values ranged from 45 to 100. The negative predictive values ranged from 53 to 100. The combined DOR was 36.02 (95%CI 15.65-82.92; I² = 65.8%; P = 0.0018). The corresponding AUC for the SROC curve was 0.92 and the Q value was 0.85.

CONCLUSION

In conclusion, the outcomes of meta-analysis indicate that during the period of patients' diagnosis in H. pylori infection, who undergoes partial gastrectomy, has high accuracy.

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori.

OBJECTIVES

To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as 13C or 14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities.

MAIN RESULTS

We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons.

AUTHORS' CONCLUSIONS

In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions.

Consensus on the clinical management, screening-to-treat, and surveillance of Helicobacter pylori infection to improve gastric cancer control on a nationwide scale

BACKGROUND

Previous international consensus statements provided general policies for the management of Helicobacter pylori infection. However, there are geographic differences in the prevalence and antimicrobial resistance of H. pylori, and in the availability of medications and endoscopy. Thus, nationwide or regional consensus statements are needed to improve control of H. pylori infection and gastric cancer.

MATERIALS AND METHODS

This consensus statement for management of H. pylori in Taiwan has three major sections: (1) optimal diagnosis and indications; (2) current treatment strategies; and (3) screening-to-treat and surveillance for control of gastric cancer. The literature review emphasized recent data for development of draft statements and determination of levels of evidence. Twenty-five Taiwan experts conducted a consensus conference, by a modified Delphi process, to modify the draft statements. Consensus, defined as an agreement of least 80% of the experts, and recommendation grade were determined by anonymous voting.

RESULTS

There were 24 consensus statements. Section 1 has seven statements on recommendations for the diagnosis and indications for treatment of H. pylori infection. Section 2 has 10 statements that provide an updated treatment algorithm for first-line, second-line, and third-line regimens. Section 3 has seven statements regarding H. pylori eradication for reducing the risk of gastric cancer, with a cost-benefit analysis. After H. pylori eradication, the consensus highlights the use of endoscopic surveillance and/or chemoprevention to further reduce the burden of gastric cancer.

CONCLUSIONS

This consensus statement has updated recommendations for improving the clinical management of H. pylori infection in areas such as Taiwan, which have high prevalence of H. pylori infection and gastric cancer.

Effect of posture on 13C-urea breath test in partial gastrectomy patients

AIM: To investigate whether posture affects the accuracy of ¹³C-urea breath test (¹³C-UBT) for Helicobacter pylori (H. pylori) detection in partial gastrectomy patients.

METHODS: We studied 156 consecutive residual stomach patients, including 76 with H. pylori infection (infection group) and 80 without H. pylori infection (control group). H. pylori infection was confirmed if both the rapid urease test and histology were positive during gastroscopy. The two groups were divided into four subgroups according to patients’ posture during the ¹³C-UBT: subgroup A, sitting position; subgroup B, supine position; subgroup C, right lateral recumbent position; and subgroup D, left lateral recumbent position. Each subject underwent the following modified ¹³C-UBT: 75 mg of ¹³C-urea (powder) in 100 mL of citric acid solution was administered, and a mouth wash was performed immediately; breath samples were then collected at baseline and at 5-min intervals up to 30 min while the position was maintained. Seven breath samples were collected for each subject. The cutoff value was 2.0‰.

RESULTS: The mean delta over baseline (DOB) values in the subgroups of the infection group were similar at 5 min (P > 0.05) and significantly higher than those in the corresponding control subgroups at all time points (P < 0.01). In the infection group, the mean DOB values in subgroup A were higher than those in other subgroups within 10 min and peaked at the 10-min point (12.4‰± 2.4‰). The values in subgroups B and C both reached their peaks at 15 min (B, 13.9‰± 1.5‰; C, 12.2‰± 1.7‰) and then decreased gradually until the 30-min point. In subgroup D, the value peaked at 20 min (14.7‰± 1.7‰). Significant differences were found between the values in subgroups D and B at both 25 min (t = 2.093, P = 0.043) and 30 min (t = 2.141, P = 0.039). At 30 min, the value in subgroup D was also significantly different from those in subgroups A and C (D vs C: t = 6.325, P = 0.000; D vs A: t = 5.912, P = 0.000). The mean DOB values of subjects with Billroth I anastomosis were higher than those of subjects with Billroth II anastomosis irrespectively of the detection time and posture (P > 0.05).

CONCLUSION: Utilization of the left lateral recumbent position during the procedure and when collecting the last breath sample may improve the diagnostic accuracy of the ¹³C-UBT in partial gastrectomy patients.

The diagnostic validity of the (13)c-urea breath test in the gastrectomized patients: single tertiary center retrospective cohort study

BACKGROUND

This study was conducted to evaluate the diagnostic validity of the (13)C-urea breath test ((13)C-UBT) in the remnant stomach after partial gastrectomy for gastric cancer.

METHODS

The (13)C-UBT results after Helicobacter pylori eradication therapy was compared with the results of endoscopic biopsy-based methods in the patients who have received partial gastrectomy for the gastric cancer.

RESULTS

Among the gastrectomized patients who showed the positive (13)C-UBT results (≥ 2.5‰, n = 47) and negative (13)C-UBT results (< 2.5‰, n = 114) after H. pylori eradication, 26 patients (16.1%) and 4 patients (2.5%) were found to show false positive and false negative results based on biopsy-based methods, respectively. The sensitivity, specificity, false positive rate, and false negative rate for the cut-off value of 2.5‰ were 84.0%, 80.9%, 19.1%, and 16.0%, respectively. The positive and negative predictive values were 44.7% and 96.5%, respectively. In the multivariate analysis, two or more H. pylori eradication therapies (odds ratio = 3.248, 95% confidence interval= 1.088-9.695, P = 0.035) was associated with a false positive result of the (13)C-UBT.

CONCLUSIONS

After partial gastrectomy, a discordant result was shown in the positive (13)C-UBT results compared to the endoscopic biopsy methods for confirming the H. pylori status after eradication. Additional endoscopic biopsy-based H. pylori tests would be helpful to avoid unnecessary treatment for H. pylori eradication in these cases.

Helicobacter pylori breath testing in an open access system has a high rate of potentially false negative results due to protocol violations

BACKGROUND

Among available tests to detect Helicobacter pylori (H. pylori), urea breath test (UBT) is the most accurate when performed correctly in research protocols with unknown validity in clinic settings.

MATERIAL AND METHODS

A total of 595 subjects at a gastroenterology clinic were tested 620 times with UBT. Detailed information about three known factors (recent proton-pump inhibitors (PPI), antibiotics, or bismuth, H. pylori eradication treatment finished <4 weeks ago, and gastric resection) to make UBT unreliable were prospectively recorded before each test.

RESULTS

Twenty-three percent (120 of 526) of all negative tests fell in one or more of the three categories, which had the potential to make UBT unreliable. Of those carried out on persons without being treated before, the potential false negative rate was 15%. Among those with previous eradication treatment, the rate was around 45%.

CONCLUSIONS

If a negative UBT could be false negative in up to 23% of cases, then it has a serious lack of negative predictive value. A negative UBT should be considered false negative until potential protocol violations are excluded.

Diagnostic performance of urea breath test, rapid urea test, and histology for Helicobacter pylori infection in patients with partial gastrectomy: a meta-analysis

BACKGROUND

Helicobacter pylori infection has been implicated in the pathogenesis of gastroduodenal diseases such as recurrent peptic ulceration and particularly residual stomach cancer in the postoperative stomach.

AIM

To determine the performance of different commonly used tests for the diagnosis of H. pylori infection in patients after partial gastrectomy.

METHODS

A systematic literature search was conducted by searching the PubMed, EMBASE and ScienceDirect databases with relevant key words. Data extraction was independently performed by two reviewers. Meta-analyses were performed for the performance of the different tests including the sensitivities, specificities, likelihood ratios (LRs), diagnostic odds ratio diagnostic odds ratio, and the summary receiver operating characteristic summary receiver operating characteristic curve. The meta-analysis was performed by Meta-DiSc software.

RESULTS

Studies showed a high degree of heterogeneity. Pooled sensitivity, specificity, LR+, LR- and diagnostic odds ratio for the different methods were: Urea breath test (9 studies): 0.77 (95% CI, 0.72-0.82), 0.89 (95% CI, 0.85-0.93), 6.32 (95% CI, 3.22-12.42), 0.27 (95% CI, 0.17-0.43), and 27.86 (95% CI, 13.27-58.49). Rapid urease test (7 studies): 0.79 (95% CI, 0.72-0.84), 0.94 (95% CI, 0.90-0.97), 10.21 (95% CI, 5.94-17.54), 0.28 (95% CI, 0.22-0.36) and 49.02 (95% CI, 24.24-99.14). Histology (3 studies): 0.93 (95% CI, 0.88-0.97), 0.85 (95% CI, 0.73-0.93), 5.88 (95% CI, 3.26-10.60), 0.09 (95% CI, 0.05- 0.15), and 97.28 (95% CI, 34.30-275.95). The corresponding summary receiver operating characteristic curves showed areas under the curves of 0.91, 0.93 and 0.96 and Q* values of 0.84, 0.86 and 0.91, respectively

CONCLUSION

Among the three commonly used tests, histological examination performs the best, followed by the rapid urease test, for the diagnosis of H. pylori infection after partial gastrectomy. Thus, histology, preferably after the rapid urease test, is recommended for the diagnosis of H. pylori infection after partial gastrectomy.

A rapid continuous-real-time 13C-urea breath test for the detection of Helicobacter pylori in patients after partial gastrectomy

INTRODUCTION

Before the development of efficient medications for peptic ulcer disease many patients were treated surgically by partial gastrectomy. The pathogenetic role of Helicobacter pylori was also not known yet. Some of these patients may therefore still harbor H. pylori in their remnant stomach as a carcinogenic agent for gastric cancer. This could be even more relevant for patients who were operated for tumors in the stomach. The efficacy of the urea breath test (UBT) is not clear in this population.

AIMS

To study the prevalence of H. pylori and to evaluate the sensitivity and specificity of the continuous UBT (BreathID) in postgastrectomized patients in Israel. In this system, the pH of the stomach is lowered by the addition of citric acid that may be beneficial in the smaller and more alkalic stomach.

METHODS

We compared retrospectively the results of our continous UBT with a rapid urease test (RUT) and the histology in all our patients who underwent gastroscopy for any clinical indication, and had a history of partial gastrectomy during the years 2002 to 2010. Only patients in whom H. pylori was tested by all the 3 methods during the same day were included in the study. We identified 76 such patients older than 18 years and performed a statistical analysis of all possibly related clinical data. The 3 methods were compared with each other.

RESULTS

H. pylori was positive in 14/76 (18.4%) patients when histology was considered as the gold standard method. The positive predictive value of the continuous UBT and the RUT was 0.64 and 0.35, respectively. The negative predictive value was high by both the methods, 0.92 and 0.95, respectively. Weight loss was correlated with positivity for H. pylori (P=0.032) and a longer gastric stump was marginally related to H. pylori (P=0.071). There was no difference for H. pylori positivity between patients with Billroth I or Billroth II operations. Prevalence of H. pylori was not lower in patients who had partial gastrectomy several years earlier.

CONCLUSIONS

The prevalence of H. pylori is considerable even several years after partial gastrectomy. The BreathID is reliable to exclude H. pylori after partial gastrectomy. The positive predictive value of the UBT is not very high but better than the RUT. We suggest that all positive patients found by the breath test should be treated. Our results support the view that alternative noninvasive methods, such as the stool antigen test should be further studied and compared with the BreathID in larger populations.

Sleeve gastrectomy leads to Helicobacter pylori eradication

BACKGROUND

The role of Helicobacter pylori (HP) in patients scheduled and undergoing laparoscopic sleeve gastrectomy (LSG) has not been previously evaluated.

METHODS

Included were obese patients presenting to our institution for LSG over 24 months. All patients had presurgical HP breath test, and the symptomatic ones received triple therapy with symptom follow-up. Post surgery, all excluded stomachs were evaluated for HP, and those that were positive performed a second 13C-urea breath test (UBT) 3 months later.

RESULTS

Forty patients underwent LSG. Male to female sex ratio was 1:3; mean age-42 years; mean weight-122 kg; and mean BMI of 43.4 kg/m2. Presurgical HP was positive in 15 (37.5%) patients (11 symptomatic and four asymptomatic). Only these 11 patients were given HP eradication therapy and all experienced complete subsequent symptom resolution. HP was detected in 17 out of the 40 (42.5%) cases of excluded stomachs. All performed a 13C-UBT 3 months post operation and only three (17.6%) tested positive.

CONCLUSIONS

HP infection is frequent in biopsies from patients with previous LSG and the majority of follow-up 13C-UBT were negative. In our small initial sample, we treated only symptomatic patients preoperatively. Routine screening for HP for all LSG patients and/or treatment for all positive ones would subject patients to expensive and unnecessary investigations. We propose that this stomach-reducing, pylorus-preserving surgery might even lead to HP eradication. The clinical implications of HP and this gastrectomy for a non-neoplastic, non-peptic indication deserve further study.

Simple and accurate (13)C-urea breath test for detection of Helicobacter pylori in the remnant stomach after surgery

BACKGROUND

The efficacy of the (13)C-urea breath test (UBT) for diagnosis of Helicobacter pylori (H. pylori) infection in the remnant stomach after surgery is a matter of controversy. We report a simple and accurate method of (13)C-UBT for diagnosis of H. pylori infection in the remnant stomach after gastrectomy.

METHODS

Eighty patients who had undergone gastrectomy with or without subsequent H. pylori eradication therapy were examined a total of 134 times for H. pylori infection by the (13)C-UBT. (13)C-Urea, 10mg per test, was used in powdered form or in the form of film-coated tablets. Breath samples were collected before and 10, 20, and 3 min after ingestion. Mucosal biopsy specimens for bacterial culture and histological examination of the remnant stomach were collected endoscopically after each (13)C-UBT test.

RESULTS

Factors that confounded the (13)C-UBT results in the remnant stomach were oral bacteria, posture, and residual food. Lying horizontally on the left side was the best position, and film-coated tablets indicated no necessity for use of mouthwash. The method of anastomosis had no significant effect on the results of the (13)C-UBT. Thirty minutes and a cutoff of 4.5 per thousand were optimal conditions for detection of H. pylori in the remnant stomach. Under these conditions, sensitivity, specificity, and accuracy were 79.4% (27/34 cases), 95.7% (44/46 cases), and 88.8% (71/80 cases), respectively, in ordinary H. pylori diagnosis, and 100% (2/2 cases), 93.3% (14/15 cases), and 94.1% (16/17 cases), respectively, in evaluating eradication at 4 weeks after treatment of H. pylori.

CONCLUSIONS

Having the patient lie horizontally on the left side, using a film-coated (13)C-urea tablet without using mouthwash, and measurement at 3 min provided a simple and accurate method of (13)C-urea breath test for detection of H. pylori in the remnant stomach after gastrectomy.

13C-urea breath test in the management of Helicobacterpylori infection

The urea breath test is a noninvasive and very accurate test for the diagnosis of Helicobacter pylori infection. However, false negative urea breath test results have been reported to occur in a considerable percentage of the individuals taking proton pump inhibitors; the interval needed to be completely confident that false negative tests had been excluded has varied among the different studies between 6 and 14 days. The impact of H(2)-receptor antagonists on the accuracy of urea breath test remains controversial, although, in contrast with proton pump inhibitors, the data suggest that H(2)-receptor antagonists, for the most part, have little effect on the result of the urea breath test. The urea breath test does not represent a suitable tool for estimating the density of H. pylori colonization. The only quantitative information to be obtained from the urea breath test is that the higher the delta value, the lower the probability of a false-positive urea breath test result. Although some authors have demonstrated a correlation between urea breath test values and histological lesions of the gastric mucosa, the practical utility of this relationship remains unclear. It has been suggested that the pretreatment urea breath test has the potential to identify patients who require modification of the standard therapeutic regimen (for example, prolonging the duration of treatment or increasing the pharmacological dose when bacterial density is high), but other studies could not confirm this relationship. Some studies have shown that the urea breath test is less accurate in patients who have undergone partial gastrectomy. Finally, in contrast with biopsy-based methods, which are responsible for a high number of false-negative results when used to diagnose H. pylori infection in patients with upper gastrointestinal bleeding, urea breath test seems not to be negatively influenced by the presence of this complication.

[Late follow-up of gastrectomized patients for peptic ulcer: clinical, endoscopic and histopathological aspects]

BACKGROUND

The gastrectomy is an uncommon procedure because the proton bomb inhibitors associated to the antibiotic outlines used to eradicate the Helicobacter pylori changed the focus of the peptic ulcer treatment.

AIMS

Later evaluation on those patients who underwent partial gastrectomy as a treatment for peptic ulcer, at that time when any drug to eradicate the Helicobacter pylori was not used. The clinical evaluation included the late postoperative symptoms and postgastrectomy syndromes like dumping, diarrhea, alkaline gastritis and nutritional aspects. The upper digestive endoscopy analysed the surgery reconstruction and the gastric stump, the duodenum and the jejunum mucosa aspects. The histopathological evaluation included looking for Helicobacter pylori by using two different methods: histology and urease test.

CASUISTIC AND METHODS

Fifty-nine patients, 44 (74.6%) male, median age 55.5 years old (range from 31 to 77 years old), who underwent a clinical interview and an upper digestive endoscopy. Paraffin blocks from the surgical specimen were reviewed in order to find out if the patients did have or did not have Helicobacter pylori before surgery.

RESULTS

The final results show that most of the patients had very good and good clinical evolution (Visick I e II) in 96%. The most common symptoms on late postoperative are mild dyspepsia with or without Helicobacter pylori, and diarrhea, anemia and dumping occurred in, respectively, 11 (18.6%), 2 (3.4%) and 2 (3.4%) cases. The Billroth I reconstruction had the best clinical results on statistical rate. The endoscopic finding showed normal results in the most number of cases, and reflux alkaline gastritis or erosive gastritis in a few cases. Ulcer recurrences were diagnosed in two patients (3.4%), and both had positive Helicobacter pylori. Most of the patients had Helicobacter pylori (86%) before surgery and also in the postoperative time (89.9%).

CONCLUSIONS

The patients had a very good clinical evolution after the gastrectomy. The Billroth I reconstruction had the best clinical results. The Helicobacter pylori is still present on gastric stump in late postoperative time, and we believe that it does not bring any negative influence to surgical results.

Efficacy of triple therapy plus cetraxate for the Helicobacter pylori eradication in partial gastrectomy patients

In the present study, we aimed to establish an additional standardized protocol with a higher H. pylori eradication rate in the remnant stomach. Fifty-five H. pylori-positive patients were randomly allocated to one of three regimens: LAC--lansoprazole, amoxicillin, and clarithromycin b.i.d. for 7 days (n = 17); LAC+CET--LAC b.i.d. plus cetraxate q.i.d. for 7 days (n = 20); and LEFT--LAC for 7 days in a horizontal body position on the left side for 30 min (n = 18). Patient compliance and side effects were checked via interviews. H. pylori eradication was successful in 75, 72, and 41% in LAC+CET, LEFT, and LAC, respectively. The eradication rate was significantly higher in LAC+CET than in LAC (P = 0.024) but not in LEFT (P = 0.058). Adverse events that occurred in each group were almost all mild ones. Cetraxate plus LAC for 1 week is a safe and effective regime for the eradication of H. pylori in patients after partial gastrectomy.

Stool antigen test for the diagnosis of Helicobacter pylori infection: a systematic review

Our aim was to review systematically the diagnostic accuracy of the Helicobacter pylori stool antigen test. Bibliographical searches were performed in several electronic databases and abstracts from congresses up to May 2003. Eighty-nine studies (10,858 patients) evaluated the stool antigen test in untreated patients. Mean sensitivity, specificity, positive predictive value and negative predictive value were 91%, 93%, 92% and 87%, respectively. Analysis of the eight studies (1399 patients) in which pretreatment evaluation of the monoclonal stool antigen test was performed showed better (p < .001) results (96%, 97%, 96% and 97%, respectively), with a clearer distinction between positive and negative results. Thirty-nine studies (3147 patients) evaluated the stool antigen test for the confirmation of H. pylori eradication 4-8 weeks after therapy, with accuracies of 86%, 92%, 76% and 93% for mean sensitivity, specificity, positive predictive value and negative predictive value, respectively. Results were similar when a gold standard based on at least two methods was used. Relatively low accuracy was reported in some posttreatment studies with the polyclonal stool antigen test. However, excellent results (p < .001) were achieved in all the six studies evaluating the monoclonal stool antigen test 4-8 weeks posttreatment. Results evaluating the stool antigen test < 4 weeks posttreatment are contradictory. Proton-pump inhibitors seem to affect the accuracy of the stool antigen test. Sensitivity and/or specificity in patients with gastrointestinal bleeding may be suboptimal. The stool antigen test performs well in children. Finally, the stool antigen test seems to be a cost-effective method.

The selection of triple therapy for Helicobacter pylori eradication in chronic renal insufficiency

AIM

To establish a triple therapy regimen for Helicobacter pylori eradication in patients with chronic renal insufficiency.

METHODS

Eighty-eight patients with chronic renal insufficiency and H. pylori infection were evenly randomized into two groups receiving 1-week lansoprazole, 30 mg, clarithromycin, 500 mg, and either amoxicillin, 750 mg, or metronidazole, 500 mg, twice daily. The adverse events and compliance with triple therapy were reviewed at the week 1 visit. Patients provided stool samples at week 6 to assess the success of H. pylori eradication by H. pylori-specific stool antigen. The serum creatinine levels were monitored at enrollment, at weeks 1, 2 and 6 and on any unscheduled visit after triple therapy.

RESULTS

The success of H. pylori eradication was higher in the lansoprazole-clarithromycin-metronidazole group than in the lansoprazole-clarithromycin-amoxicillin group (intention-to-treat analysis: 84% vs. 66%, P < 0.05: per protocol analysis: 93% vs. 76%, P < 0.05). Complete drug compliance was also better in the lansoprazole-clarithromycin-metronidazole group than in the lansoprazole-clarithromycin-amoxicillin group (77% vs. 52%, P < 0.05). Patients in the lansoprazole-clarithromycin-metronidazole group had a lower risk of acute renal failure than those in the lansoprazole-clarithromycin-amoxicillin group (2% vs. 18%, P < 0.05; relative risk, 0.128, 95% confidence interval, 0.016-0.979).

CONCLUSIONS

Triple therapy with metronidazole and clarithromycin, but not amoxicillin, can be used for H. pylori eradication in patients with chronic renal insufficiency, because it is more effective, well tolerated and less likely to cause deterioration of renal function.

Studies of 13C-urea breath test for diagnosis of Helicobacter pylori infection in patients after partial gastrectomy

BACKGROUND/AIMS

Many of the reports on the diagnostic efficacy of the 13C-urea breath test (13C-UBT) for the detection of Helicobacter pylori in the residual stomach have shown negative results. We conducted an evaluation to establish a standardized protocol and an appropriate cutoff value for 13C-UBT in partial gastrectomy patients.

METHODS

Forty-two patients undergoing partial gastrectomy were included. Three gastric biopsies from the anastomotic site and mid-to-high body were taken at panendoscopy for histology, culture and rapid urease test (RUT). The 13C-UBT protocol included ingestion of 100 mg 13C-urea, use of mouthwash, and the body in a horizontal position on the left side. Six breath samples were taken after ingestion.

RESULTS

The Delta 13CO2 values were significantly elevated in infected patients at all time points, and values were higher at 20 min and thereafter than at an earlier time point. The sensitivity of 13C-UBT was 96.3% with the cutoff of 2.0 per thousand at 40 min. The accuracy rates were highest with 13C-UBT, culture, RUT and histological tests, in that order.

CONCLUSION

Forty minutes and a cutoff of 2.0 per thousand were found to be optimal for the test, with the body position horizontal on the left side. In the present protocol 13C-UBT appears to be a reliable tool with the same accuracy rate as other routine tests in patients with a remnant stomach.

Five minute endoscopic urea breath test with 25 mg of (13)C-urea in the management of Helicobacter pylori infection

OBJECTIVE

The endoscopic (13)C-urea breath test ((13)C-EUBT), which combines the urea breath test (UBT) with endoscopy, provides high accuracy for the detection of Helicobacter pylori. This study was conducted to determine whether the (13)C-EUBT using low doses of urea and short sampling times could preserve accuracy in the management of H. pylori infection.

METHODS

Three hundred and twenty-five patients were randomized to receive the EUBT with 100, 50 or 25 mg of (13)C-urea by endoscopic spraying. The breath samples collected at 5, 10 and 20 min were analysed using an isotope selected non-dispersive infrared spectrometer. H. pylori infection was assessed by the rapid urease test and histology. In each sampling schedule and protocol, cut-off values were calculated by a receiver operating characteristic curve. We applied the EUBT with 25 mg of (13)C-urea at 5 min to the assessment of eradication in 135 patients who had received the antimicrobial treatment or to the detection of the organism in 61 patients with previous partial gastrectomy.

RESULTS

Based on histology and the urease test, patients who had discordant results were excluded from the analysis. Using 100 mg of urea, the sensitivity and specificity of the test were both 100% at 10 and 20 min, and the sensitivity and specificity at 5 min were best with 98.6% and 100%, respectively. With 50 mg, they were both 100% at 20 min, and the best combination of sensitivity and specificity at 5 and 10 min was 97.3-96.6% and 97.3-100%, respectively. Even with 25 mg, the sensitivity and specificity were both 100.0% at 20 min, and at the 5 min and 10 min time point, the EUBT yielded a sensitivity of 98.7% and a specificity of 100%. There was a significant positive correlation between the test values of the 5 min (13)C-EUBT with 25 mg of test urea and those of the conventional UBT. The 5 min EUBT with (13)C-urea offered high accuracy in the assessment of H. pylori eradication, with the sensitivity and specificity being 100% and 96.4%, respectively. In patients with previous gastrectomy, the EUBT provided acceptable accuracy (a sensitivity of 96.4% and a specificity of 97.0%).

CONCLUSIONS

Our results indicate that the (13)C-EUBT is an accurate method for detecting H. pylori infection. The EUBT using only 25 mg of (13)C-urea at the early (5 min) time point has satisfactory diagnostic efficacy in pre- and post-eradication treatment settings, providing a less expensive and more rapid way of performing the test. The EUBT may be a reliable method of assessing H. pylori status in the remnant stomach.

Stool antigen assay to screen H. pylori infection and to assess the success of 3-Day and 7-Day eradication therapy in the patients with partial gastrectomy

BACKGROUND

Even after partial gastrectomy, Helicobacter pylori may persist in the residual stomach but be less abundant in the bacterial load. H. pylori stool antigen is a reliable noninvasive tool to detect H. pylori infection in patients without gastrectomy. We thus test whether [1] the course of H. pylori eradication therapy could be diminished [2]; stool antigen can effectively detect H. pylori infection for the patients with gastrectomy.

METHODS

One hundred and eight patients who had undergone partial gastrectomy were enrolled to receive panendoscopy and provided stool samples for H. pylori stool antigen within 3 days after endoscopy. The H. pylori-infected patients were then randomized to receive either a 3- or 7-day triple therapy for H. pylori eradication. Six weeks later, to evaluate the success of H. pylori eradication, patients received a follow-up endoscopy and again provided stool samples for H. pylori stool antigen.

RESULTS

Seventy out of 108 patients, proven to have H. pylori infection, were evenly randomized into 3-day and 7-day therapy groups. The H. pylori eradication rates were similar between the 3-day and 7-day triple therapy (90.9 vs. 93.8%, p >.05). Before therapy, the H. pylori stool antigen was 93% sensitive and 100% specific to detect H. pylori. After therapy, H. pylori stool antigen remain 100% sensitive and 88.3% specific to detect the failure of eradication therapy.

CONCLUSION

H. pylori stool antigen is a highly reliable tool to screen H. pylori infection before therapy and to assess the success of eradication therapy in partial gastrectomy patients. To eradicate H. pylori infection for patients with partial gastrectomy, the duration of triple therapy can be shortened.