Negative effect of ranitidine on the results of urea breath test for the diagnosis of Helicobacter pylori

Diagnosis of Helicobacter pylori Infection and Recent Advances

BACKGROUND

Helicobacter pylori (H. pylori) infects approximately 50% of the world population. Its infection is associated with gastropathies, extra-gastric digestive diseases, and diseases of other systems. There is a canonical process from acute-on-chronic inflammation, chronic atrophic gastritis (CAG), intestinal metaplasia (IM), dysplasia, and intraepithelial neoplasia, eventually to gastric cancer (GC). H. pylori eradication abolishes the inflammatory response and early treatment prevents the progression to preneoplastic lesions.

METHODS

the test-and-treat strategy, endoscopy-based strategy, and screen-and-treat strategy are recommended to prevent GC based on risk stratification, prevalence, and patients' clinical manifestations and conditions. Challenges contain false-negative results, increasing antibiotic resistance, decreasing eradication rate, and poor retesting rate. Present diagnosis methods are mainly based on invasive endoscopy and noninvasive laboratory testing.

RESULTS

to improve the accuracy and effectiveness and reduce the missed diagnosis, some advances were achieved including newer imaging techniques (such as image-enhanced endoscopy (IEE), artificial intelligence (AI) technology, and quantitative real-time polymerase chain reaction (qPCR) and digital PCR (dPCR).

CONCLUSION

in the article, we summarized the diagnosis methods of H. pylori infection and recent advances, further finding out the opportunities in challenges.

European guideline on indications, performance and clinical impact of 13 C-breath tests in adult and pediatric patients: An EAGEN, ESNM, and ESPGHAN consensus, supported by EPC

Introduction

¹³C‐breath tests are valuable, noninvasive diagnostic tests that can be widely applied for the assessment of gastroenterological symptoms and diseases. Currently, the potential of these tests is compromised by a lack of standardization regarding performance and interpretation among expert centers.

Methods

This consensus‐based clinical practice guideline defines the clinical indications, performance, and interpretation of ¹³C‐breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 43 experts from 18 European countries. Consensus on individual statements and recommendations was established if ≥ 80% of reviewers agreed and <10% disagreed.

Results

The guideline gives an overview over general methodology of ¹³C‐breath testing and provides recommendations for the use of ¹³C‐breath tests to diagnose Helicobacter pylori infection, measure gastric emptying time, and monitor pancreatic exocrine and liver function in adult and pediatric patients. Other potential applications of ¹³C‐breath testing are summarized briefly. The recommendations specifically detail when and how individual ¹³C‐breath tests should be performed including examples for well‐established test protocols, patient preparation, and reporting of test results.

Conclusion

This clinical practice guideline should improve pan‐European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, this guideline identifies areas of future clinical research involving the use of ¹³C‐breath tests.

Lack of almagate interference in breath test results for Helicobacter pylori diagnosis (Almatest study)

OBJECTIVE

The ¹³C-urea breath test (UBT) is the most widely used non-invasive diagnostic test for Helicobacter pylori. Debate continues to surround the possible interference of antacid intake on its result. This study aims to confirm the non-interference of almagate in the determination of H. pylori by UBT.

PATIENTS AND METHODS

Observational, multicentre study in adult patients treated with almagate in whom a UBT (TAUKIT®) was indicated. When the UBT result was negative, use of almagate was stopped for 30 days and the UBT was repeated. When the result was positive, no further determinations were made. The primary endpoint was the percentage of patients who, having had a negative result in the first breath test, were positive in the second after having stopped taking almagate (UBT false negatives, possibly attributable to almagate).

RESULTS

Of the 167 evaluable patients, 59% were female, average age was 49 and 97% had gastrointestinal symptoms. The result of the first UBT was negative in 71% of cases. Of these, in the second UBT test after stopping the almagate, the negative result was confirmed in 97.5%. Out of the total number of cases evaluated, the rate of false negatives was 1.8%.

CONCLUSIONS

Taking almagate has minimal or no interference in the result of UBT for the diagnosis of H. pylori infection. It can therefore be used in the weeks prior to a UBT.

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.

Helicobacter pylori management in ASEAN: The Bangkok consensus report

Helicobacter pylori (H. pylori) infection remains to be the major cause of important upper gastrointestinal diseases such as chronic gastritis, peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. H. pylori management in ASEAN: the Bangkok consensus report gathered key opinion leaders for the region to review and evaluate clinical aspects of H. pylori infection and to develop consensus statements, rationales, and grades of recommendation for the management of H. pylori infection in clinical practice in ASEAN countries. This ASEAN Consensus consisted of 34 international experts from 10 ASEAN countries, Japan, Taiwan, and the United States. The meeting mainly focused on four issues: (i) epidemiology and disease association; (ii) diagnostic tests; (iii) management; and (iv) follow-up after eradication. The final results of each workshop were presented for consensus voting by all participants. Statements, rationale, and recommendations were developed from the available current evidence to help clinicians in the diagnosis and treatment of H. pylori and its clinical diseases.

Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report

Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

[Clinical practice guideline on the management of patients with dyspepsia. Update 2012]

The aim of the Clinical Practice Guideline (CPG) on the Management of Patients with Dyspepsia is to generate recommendations on the optimal approach to dyspepsia in the primary care and specialized outpatient setting. The main objective of this CPG is to help to optimize the diagnostic process, identifying patients with a low risk of a serious organic disease (mainly tumoral), who could be safely managed without the need for invasive diagnostic tests and/or referral to a specialist. The importance of this aim lies in the need to accurately diagnose patients with esophagogastric cancer and correctly treat peptic ulcer while, at the same time, reduce negative endoscopies in order to appropriately use the available healthcare resources. This CPG reviews the initial strategies that can be used in patients with uninvestigated dyspepsia and evaluates the possible decision to begin empirical therapy or to investigate the existence of a lesion that could explain the symptoms. This CPG also discusses functional dyspepsia, which encompasses all patients with dyspepsia with no demonstrable cause on endoscopy. Recommendations for the diagnosis and treatment of peptic ulcer and Helicobacter pylori infection are also made. To classify the scientific evidence and strengthen the recommendations, the GRADE (Grading of Recommendations Assessment, Development and Evaluation Working Group) system has been used (http://www.gradeworkinggroup.org/).

[Clinical practice guideline on the management of patients with dyspepsia. Update 2012]

The aim of the Clinical Practice Guideline (CPG) on the Management of Patients with Dyspepsia is to generate recommendations on the optimal approach to dyspepsia in the primary care and specialized outpatient setting. The main objective of this CPG is to help to optimize the diagnostic process, identifying patients with a low risk of a serious organic disease (mainly tumoral), who could be safely managed without the need for invasive diagnostic tests and/or referral to a specialist. The importance of this aim lies in the need to accurately diagnose patients with esophagogastric cancer and correctly treat peptic ulcer while, at the same time, reduce negative endoscopies in order to appropriately use the available healthcare resources.This CPG reviews the initial strategies that can be used in patients with uninvestigated dyspepsia and evaluates the possible decision to begin empirical therapy or to investigate the existence of a lesion that could explain the symptoms. This CPG also discusses functional dyspepsia, which encompasses all patients with dyspepsia with no demonstrable cause on endoscopy. Recommendations for the diagnosis and treatment of peptic ulcer and Helicobacter pylori infection are also made. To classify the scientific evidence and strengthen the recommendations, the GRADE (Grading of Recommendations Assessment, Development and Evaluation Working Group) system has been used (http://www.gradeworkinggroup.org/).

Performance of acidified 14C-urea capsule breath test during pantoprazole and ranitidine treatment

BACKGROUND AND AIM

Urea breath test (UBT) results could be false negative in patients taking antisecretory drugs. This effect would be prevented by citric acid administration during UBT. We prospectively investigated whether acidified 14C-urea capsule prevents false negative UBT results in patients taking antisecretory drugs and show interference with the duration of medications.

METHODS

Sixty Helicobacter pylori positive patients were included. Pantoprazole (40 mg/day) was given to 27 patients for 28 days and ranitidine (300 mg. o.d.) to 33 patients for 60 days. Urea breath tests were repeated on days 14 and 28 in both groups and on day 60 in the ranitidine group.

RESULTS

The baseline mean breath counts of two groups did not show any significant difference. Pantoprazole led to a significant decrease in mean breath counts on day 14 (P < 0.005). Six of 27 and 3 of 25 patients taking pantoprazole developed negative or equivocal UBT results on days 14 and 28, respectively. Two of 32, 2 of 32 and 3 of 21 patients taking ranitidine developed negative or equivocal UBT results on days 14, 28 and 60, respectively.

CONCLUSIONS

The use of acidified 14C-urea capsule did not prevent false negative UBT results in patients taking pantoprazole and ranitidine, and the duration of medication does not affect the test results.

Could the simplified (14)C urea breath test be a new standard in noninvasive diagnosis of Helicobacter pylori infection? Ann Nucl Med. 2008;22:611-616. [PMID: 18756364 DOI: 10.1007/s12149-008-0168-6]

OBJECTIVE

The carbon-14 ((14)C) urea breath test (UBT) is a reliable and noninvasive technique for the diagnosis of Helicobacter pylori (HP) infection. The diagnostic performance of a new practical and low dose (14)C UBT system (Heliprobe, Stockholm, Sweden) was compared with those of other diagnostic tests, namely, rapid urease test (RUT), histopathology, and DNA detection using polymerase chain reaction (PCR).

METHODS

Eighty-nine patients (mean age = 45 +/- 13, 30 men) with dyspeptic complaints who underwent an endoscopic procedure were studied. Biopsy specimens acquired during the procedure were subjected to RUT, histopathological examination using hematoxylin and eosin (HP-HE) and PCR. All patients underwent UBT using the Heliprobe system on a different day. The gold standard for HP positivity was defined as any two of the three tests being positive, excluding UBT, and the sensitivity and specificity of any single test alone were determined using this gold standard. Whenever only one test was positive, it was considered to be a false-positive one.

RESULTS

With the gold standard used in this study, 59 (66%) patients were diagnosed HP positive. The Heliprobe method detected HP infection with 96.6% sensitivity and 100% specificity and had the best diagnostic performance when compared with all the other methods. The sensitivity and specificity of the other methods for the detection of HP positivity were 89.8% and 100% for RUT, 93.2% and 63.3% for PCR, and 93.2% and 76.6% for HP-HE, respectively. Areas under the receiver-operating characteristic were 0.977 for UBT, 0.947 for RUT, 0.84 for HP-HE, and 0.775 for PCR.

CONCLUSIONS

Using a combination of invasive diagnostic tests as the gold standard, Heliprobe UBT was found to be highly sensitive and specific for the diagnosis of HP infection in patients with dyspeptic complaints.

American College of Gastroenterology guideline on the management of Helicobacter pylori infection

Helicobacter pylori (H. pylori) remains a prevalent, worldwide, chronic infection. Though the prevalence of this infection appears to be decreasing in many parts of the world, H. pylori remains an important factor linked to the development of peptic ulcer disease, gastric malignanc and dyspeptic symptoms. Whether to test for H. pylori in patients with functional dyspepsia, gastroesophageal reflux disease (GERD), patients taking nonsteroidal antiinflammatory drugs, with iron deficiency anemia, or who are at greater risk of developing gastric cancer remains controversial. H. pylori can be diagnosed by endoscopic or nonendoscopic methods. A variety of factors including the need for endoscopy, pretest probability of infection, local availability, and an understanding of the performance characteristics and cost of the individual tests influences choice of evaluation in a given patient. Testing to prove eradication should be performed in patients who receive treatment of H. pylori for peptic ulcer disease, individuals with persistent dyspeptic symptoms despite the test-and-treat strategy, those with H. pylori-associated MALT lymphoma, and individuals who have undergone resection of early gastric cancer. Recent studies suggest that eradication rates achieved by first-line treatment with a proton pump inhibitor (PPI), clarithromycin, and amoxicillin have decreased to 70-85%, in part due to increasing clarithromycin resistance. Eradication rates may also be lower with 7 versus 14-day regimens. Bismuth-containing quadruple regimens for 7-14 days are another first-line treatment option. Sequential therapy for 10 days has shown promise in Europe but requires validation in North America. The most commonly used salvage regimen in patients with persistent H. pylori is bismuth quadruple therapy. Recent data suggest that a PPI, levofloxacin, and amoxicillin for 10 days is more effective and better tolerated than bismuth quadruple therapy for persistent H. pylori infection, though this needs to be validated in the United States.

Accuracy of Helicobacter pylori diagnostic tests in patients with bleeding peptic ulcer: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and a meta-analysis of diagnostic accuracy of the different tests aimed to detect Helicobacter pylori infection in patients with upper gastrointestinal bleeding (UGIB).

SELECTION OF STUDIES

assessing the accuracy of H. pylori diagnostic methods in patients with UGIB.

SEARCH STRATEGY

electronic bibliographical searches.

DATA EXTRACTION

independently done by two reviewers.

DATA SYNTHESIS

meta-analyses of the different tests were performed combining the sensitivities, specificities, and likelihood ratios (LRs) of the individual studies.

RESULTS

Studies showed a high degree of heterogeneity. Pooled sensitivity, specificity, LR+ and LR- (95% confidence interval (CI)) for the different methods were: Rapid urease test (16 studies/1,417 patients): 0.67 (0.64-0.70), 0.93 (0.90-0.96), 9.6 (5.1-18.1), and 0.31 (0.22-0.44). Histology (10 studies/827 patients): 0.70 (0.66-0.74), 0.90 (0.85-0.94), 6.7 (2.5-18.4), and 0.23 (0.12-0.46). Culture (3 studies/314 patients): 0.45 (0.39-0.51), 0.98 (0.92-1.00), 19.6 (4-96), and 0.31 (0.05-1.9). Urea breath test (8 studies/520 patients): 0.93 (0.90-0.95), 0.92 (0.87-0.96), 9.5 (3.9-23.3), and 0.11 (0.07-0.16). Stool antigen test (6 studies/377 patients): 0.87 (0.82-0.91), 0.70 (0.62-0.78), 2.3 (1.4-4), and 0.2 (0.13-0.3). Serology (9 studies/803 patients): 0.88 (0.85-0.90), 0.69 (0.62-0.75), 2.5 (1.6-4.1), and 0.25 (0.19-0.33).

CONCLUSION

Biopsy-based methods, such as rapid urease test, histology, and culture, have a low sensitivity, but a high specificity, in patients with UGIB. The accuracy of 13C-urea breath test remains very high in these patients. Stool antigen test is less accurate in UGIB. Although serology seems not to be influenced by UGIB, it cannot be recommended as the first diagnostic test for H. pylori infection in this setting.

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.

Helicobacter pylori infection diagnosis in hospitalised elderly patients: the stool antigen test (HpSA) in comparison with other methods

BACKGROUND AND AIMS

Helicobacter pylori (Hp) infection prevalence increases with age. In elderly patients, who often do not collaborate and who are affected by multiple pathologies, worldwide-recognised invasive and non-invasive methods (histology and Urea Breath Test) are not easy to apply. A new test based on the detection of Hp antigens in the stool (HpSA test) is now available. The aim of our study was to evaluate the sensitivity and specificity of the HpSA test, and the interference of drugs (acid suppression, antibiotics) on test performance.

METHODS

Hp infection was detected by UBT, HpSA and histology in 122 hospitalised elderly subjects, divided into two groups according to therapy in the last month. Subjects were classified as being Hp-positive if two test results (histology and UBT) were positive, and Hp-negative if the same two test results were negative.

RESULTS

The sensitivity and specificity of the HpSA test compared with two tests (histology and UBT) were respectively 76 and 95%. In the group of patients who had not received drugs, the sensitivity and specificity of the HpSA test were respectively 76 and 96%. Instead, in the group of patients who had received pharmacological therapy, sensitivity and specificity values were respectively 67 and 100%. HpSA-positive patients had received acid suppression for 9.2 +/- 8.9 days, and false-negative patients for 27.2 +/- 9.9 days.

CONCLUSIONS

The HpSA test is simple, inexpensive, and non-invasive for Hp detection, especially in elderly subjects with no compliance. It is influenced only after several days by therapy common in the elderly.

Masking of 13C urea breath test by proton pump inhibitors is dependent on type of medication: comparison between omeprazole, pantoprazole, lansoprazole and esomeprazole

BACKGROUND

The need to withhold acid suppression therapy while awaiting urea breath test results is a common clinical problem in symptomatic patients. It is unclear at present if the dose or type of proton pump inhibitor or the type of test meal govern the apparent masking effect of proton pump inhibitors on the urea breath test.

AIM

To prospectively evaluate Helicobacter pylori detection rates during treatment with four different proton pump inhibitors, utilizing a high-dose citric acid-based 13C urea breath test.

METHODS

Patients positive for Helicobacter pylori by urea breath test were randomized to receive either omeprazole 20 mg/day, pantoprazole 40 mg/day, lansoprazole 30 mg/day or esomeprazole 40 mg/day for 14 days. A repeat breath test was performed on day 14 of treatment.

RESULTS

One hundred and seventy-nine patients, mean age 45.8 +/- 16.8, completed the study. Treatment with omeprazole or pantoprazole prior to urea breath test (UBT) was associated with low false negative results, while lansoprazole and esomeprazole caused clinically unacceptable high false negative rates (pantoprazole 2.2% vs. lansoprazole 16.6%, P = 0.02, vs. esomeprazole 13.6%, P = 0.05; omeprazole 4.1% vs. lansoprazole 16.6%, P = 0.05).

CONCLUSIONS

Proton pump inhibitor-induced false negative results on high-dose citric acid based urea breath test vary with the type of proton pump inhibitor used. Selection of the appropriate test meal and proton pump inhibitor may allow symptomatic individuals to continue their proton pump inhibitors prior to performing a urea breath test.

Effect of proton pump inhibitors and antacid therapy on 13C urea breath tests and stool test for Helicobacter pylori infection

OBJECTIVE

There is uncertainty about the best method of testing patients for Helicobacter pylori (H. pylori) infection while they are taking proton pump inhibitors. The aim of this study was to determine: (i) if the decreased sensitivity of the urea breath test during proton pump inhibitor is corrected by different techniques for breath testing and (ii) if the sensitivity of stool test is decreased with the administration of proton pump inhibitors.

METHODS

Prospective randomized single-blind study was performed in a tertiary care university hospital. Out of 72 H. pylori infected patients endoscoped for upper abdominal symptoms 48 were randomized to proton pump inhibitors (omeprazole 20 mg each day or esomeprazole 40 mg each day) and 24 to antacid (aluminum hydroxide 800 mg each day) for 14 days. Several breath tests (standard 75 mg (13)C-UBT with citric acid, with orange juice, a tablet breath test with 100 and 50 mg of (13)C), and a stool test were carried out. Baseline samples were collected before and after treatment.

RESULTS

The baseline sensitivity for all breath tests was 100% in both groups; for stool test it was 97.8% (95% CI: 88.7-96.6) and 90% (95% CI: 69.9-97.2) in the proton pump inhibitor and antacid group, respectively. After treatment, the sensitivity of tests was significantly low (UBTs range: 77.1%-85.4%; stool test: 83%; 95% CI: 63.9-91.1), while it was unchanged in the antacid group.

CONCLUSIONS

False negative breath and stool tests are equally common in patients taking proton pump inhibitors. Antacids do not impair the sensitivity of the breath tests or the stool test.

False negative urea breath tests with H2-receptor antagonists: interactions between Helicobacter pylori density and pH

BACKGROUND

We studied the effects of famotidine, sodium bicarbonate, and citric acid on the 13C-urea breath test (UBT).

METHODS

Helicobacter pylori-infected volunteers received a UBT, 40 mg of famotidine at bedtime, and a second UBT (pudding test meal, 648 mg NaHCO3 tablet then 125 mg of urea in 200 ml of water containing 650 mg of NaHCO3). Experiment 2 consisted of four UBTs. Two were standard citric acid UBTs with 75 mg of urea and 2 g citric acid and two were sequential bicarbonate-citric acid UBTs. Sequential UBTs consisted of administration of a 648 mg bicarbonate tablet with 50 g of Polycose in 200 ml of water. Five minutes later, 125 mg of 13C-urea was given in 75 ml of water containing 650 mg of NaHCO3. Breath samples were collected after 15 minutes. Then, to acutely acidify the stomach, 4 g of citric acid was given in 200 ml of water. A second breath sample was collected 15 minutes after the citric acid. The standard UBTs were done before and after 6 days of famotidine (40 mg b.i.d.). Sequential UBTs were done after 1 and 6 days of famotidine therapy. Gastric biopsies for histology, culture, and mucosal cytokines were assessed before and after 6 days of famotidine.

RESULTS

Eighteen subjects participated, 10 in each experiment; seven had endoscopy with biopsy. Famotidine/ bicarbonate resulted an approximately 50% fall in UBT values (p = .021) with 10% becoming negative. The gastric pH increased from 5.1 +/- 0.5 to 6.7 +/- 0.2 (p = .03) although no pH value predicted the occurrence of false negative results. Under famotidine acid suppression, NaHCO3 reduced the delta over baseline (DOB) by 63% (p = .021). This was reversed with citric acid. Histology showed a H2-receptor antagonist-associated increase in the depth of gastric corpus inflammation.

CONCLUSIONS

H2-receptor antagonists differ from proton pump inhibitors as high intragastric pH may cause a reduction in urease activity, unrelated to a reduced bacterial load and reversed by citric acid.

Lack of accuracy of the noninvasive Helicobacter pylori stool antigen test in patients with gastroduodenal ulcer bleeding

OBJECTIVE

Oral presentation at Digestive Diseases Week, San Francisco, California, May 2002. The antigen-based stool assay has proven to be accurate in diagnosing Helicobacter pylori infection in dyspeptic patients. We evaluated the H. pylori antigen-based stool assay (HpSA) in patients with peptic ulcer bleeding (PUB).

METHODS

Thirty-six patients with PUB were endoscoped, and antral and corpus biopsy specimens were taken for rapid urease test (RUT), histology, and culture. The first stool sample after admission was collected for the HpSA test. The gold standard was defined as either positive culture or positive RUT and histology. If only RUT or histology was positive, this was defined as indeterminate. To evaluate cross-reaction with blood constituents, citrated blood samples from 10 healthy volunteers (nine H. pylori serology negative and one H. pylori serology positive) were assessed by the HpSA test.

RESULTS

A total of 36 consecutive patients with PUB (21 male) with a mean age of 69.5 yr were included in the study. Using the gold standard, the sensitivity and specificity of the HpSA test were 100% and 52%, respectively. Citrated blood samples of three H. pylori negative and one H. pylori positive volunteer gave a positive result in the HpSA test, suggesting cross-reaction with blood con stituents.

CONCLUSIONS

The HpSA test gave a high number of false- positive results in patients with PUB, probably because of blood constituents cross-reacting in the enzyme immunoassay. The HpSA test is not accurate for testing H. pylori infection in patients with PUB.

Circadian pattern of intragastric acidity in patients with non-erosive reflux disease (NERD)

BACKGROUND

Most patients with gastro-oesophageal reflux disease have non-erosive reflux disease. Proton pump inhibitors are less effective than expected in these patients, but no previous study has measured their 24-h gastric pH values.

AIMS

To evaluate whether there are differences in 24-h intragastric acidity between reflux patients with and without oesophagitis and controls. The influence of Helicobacter pylori on the gastric pH of reflux patients was also assessed.

METHODS

Sixty-three consecutive patients with gastro-oesophageal reflux disease symptoms who agreed to undergo endoscopy and 24-h pH-metry were recruited. Twenty-five (39%) had erosive oesophagitis and 38 (61%) did not. H. pylori was diagnosed by CLO test, histology and 13C-urea breath test. Gastric pH was also measured in 30 controls without digestive symptoms.

RESULTS

H. pylori was found in seven of the 25 (28%) patients with oesophagitis and 14 of the 38 (37%) patients with non-erosive reflux disease. Oesophageal pH-metry was abnormal in 21 of the 25 (84%) patients with oesophagitis and in 32 of the 38 (84%) patients with non-erosive reflux disease. The median gastric pH did not differ between patients with and without oesophagitis or between them and controls during the 24 h (P = 0.8) and other time intervals (P = 0.2-0.4). The gastric pH did not differ between infected and non-infected patients with oesophagitis (P = 0.2-0.4) or non-erosive reflux disease (P = 0.3-0.8).

CONCLUSIONS

The circadian pattern of intragastric acidity does not differ between patients with non-erosive reflux disease and oesophagitis. Moreover, the study confirms that H. pylori infection does not affect the gastric pH in either group of reflux patients.

Influence of lansoprazole, famotidine, roxatidine and rebamipide administration on the urea breath test for the diagnosis of Helicobacter pylori infection

BACKGROUND AND AIM

The sensitivity of the urea breath test (UBT) has been reported to be influenced by the administration of omeprazole, lansoprazole and ranitidine. However, it is unclear whether other H2 receptor antagonists (H2RA), except ranitidine, and rebamipide, a mucosal protective agent, affect UBT sensitivity. The aim of this study is to clarify the effects of lansoprazole, famotidine, roxatidine and rebamipide administration on UBT sensitivity.

METHODS

Subjects comprised 30 volunteers with Helicobacter pylori infection. All subjects were examined by the 13C-UBT on four occasions: (i) without medication (control); (ii) after the administration of 30 mg lansoprazole (u.i.d) for 14 days; (iii) after the administration of 100 mg rebamipide (t.i.d) for 14 days; and (iv) after the administration of 20 mg famotidine or 75 mg roxatidine (b.i.d) for 14 days. In the H2RA study, individuals were randomized into two groups of 15 subjects and were administered either famotidine or roxatidine.

RESULTS

Five of the 30 cases administered lansoprazole and one of the 15 cases given roxatidine gave a false-negative UBT result. No negative UBT results were observed in patients administered famotidine or rebamipide.

CONCLUSION

Patients showing negative UBT results during the administration of proton pump inhibitors and H2RA should be re-examined after the cessation of these drugs to confirm the true negativity of H. pylori infection.

Effect of proton pump inhibitors on the continuous real time (13)C-urea breath test

OBJECTIVE

The aim of this study was to evaluate the accuracy of a new, continuous real time (13)C-urea breath test, BreathID, for the diagnosis of Helicobacter pylori in patients taking proton pump inhibitors (PPIs).

METHODS

Fifty-two consecutive patients, positive for H. pylori by BreathID, were prospectively evaluated. Patients were randomized to receive either omeprazole 20 mg/day or pantoprazole 40 mg/day for 14 days. A repeat breath test was performed on day 14 while patients received their last PPI pill. Patients were given a test drink containing 75 mg (13)C-urea and 4.0 g citric acid. Real time, continuously sampled expired (13)CO(2), obtained within 6-20 min, was compared with measurement of expired (13)CO(2) by isotope ratio mass spectrometry (IRMS).

RESULTS

A full set of test data was available for 43 patients. After 14 days of treatment with PPIs, false negative detection of H. pylori occurred in only 1/43 (2.3%) patients examined by continuous real time (13)C-urea breath test compared with 2/43 (4.6%) patients examined by IRMS. With the exception of one case, complete agreement was observed between BreathID and the IRMS breath tests at both baseline and after PPI treatment. PPI treatment was associated with three different types of responses on UBT: 1) one third of the patients developed a significant decrease in the (13)CO(2)/(12)CO(2) excretion, 2) roughly one third developed a significant increase in the post-PPI breath test results, and 3) results did not change significantly in the remaining patients. Linear regression analysis of 43 H. pylori-positive subjects indicated a significant positive association between baseline and post-PPI Delta (13)CO(2)/(12)CO(2) excretion.

CONCLUSIONS

The use of a single test drink containing 4.0 g citric acid in BreathID, resulted in a low number of false negative results associated with sustained PPI treatment. Although there were some differences between BreathID versus IRMS, the type of PPI and the sampling method used do not appear to play a critical role in the detection of H. pylori by BreathID. According to these results, BreathID is a reliable tool for testing H. pylori in patients taking PPIs.

Review article: Helicobacter pylori infection in peptic ulcer haemorrhage

In this overview, medical advice for routine clinical practice regarding peptic ulcer haemorrhage (PUH) is given, based on the extensive literature about Helicobacter pylori and the controversial results about the interaction of H. pylori infection and nonsteriodal anti-inflammatory drug (NSAID) use. PUH remains an important emergency situation with an incidence between 32 and 51/100 000 persons per year. There is a high association between H. pylori infection and peptic ulcer disease. The association between H. pylori infection and PUH is less clear, but a strong argument for the aetiological role is the fact that eradication of H. pylori decreases recurrence of bleeding. NSAID use is another important risk factor for PUH. H. pylori infection and NSAID use seem to act independently, although some studies show a synergistic interaction while other studies report that H. pylori is protective against the development of PUH in NSAID users. All patients with PUH should be tested for H. pylori infection, regardless of the use of NSAIDs. Because invasive tests are less sensitive in PUH patients, negative tests in patients with no other risk factors should be confirmed by serology or urea breath test (UBT). Eradication therapy with a proton pump inhibitor or ranitidine bismuth citrate-based triple therapy should be given to all H. pylori-positive patients. Only for nonaspirin-NSAID users does the effect of eradication therapy on the healing of gastric ulcers remain controversial, but currently we also advise eradication of H. pylori in this subgroup. After eradication therapy, acid-suppressant therapy is advised to heal the ulcer. The success of eradication should always be confirmed because of the risk of recurrence of peptic ulcer disease and bleeding in H. pylori-infected patients.