Appropriateness of urea breath test: a prospective observational study based on Maastricht 2000 guidelines

Diagnostic and Therapeutic Management of Helicobacter pylori Infection in Primary Care: Perspective of Application in France and Narrative Review of the Literature

BACKGROUND

Helicobacter pylori (Hp) infection affects 30% to 40% of people in industrialized countries.

AIM

This study aimed to synthesize knowledge on the diagnostic and therapeutic management of Hp infection in general practice in people under 40 years of age.

METHOD

A narrative review of the literature with an inductive content analysis of the articles was performed.

RESULTS

The extracted data (22 articles out of 106 included after screening of 965 articles) determined three areas of analysis: indications for screening, methods of screening and diagnosis by non-invasive tests, and treatment modalities.

DISCUSSION

Targeted, easily performed screening with noninvasive tests is recommended for patients younger than 45 years of age with no family history of gastric cancer and symptoms of dyspepsia without warning signs. Given their proximity to the general population and their coverage of the territory, general practitioners are ideally positioned. Treatment modalities are well-codified and feasible in primary care. Simplifying the recommendations available to them would optimize the identification of patients at risk and the management of Hp infection. Informing, educating, involving, supporting, and promoting the control of Hp infection in primary care will be future goals. Further research is needed in primary care to evaluate the impact of new procedures on Hp control.

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.

Rationale in diagnosis and screening of atrophic gastritis with stomach-specific plasma biomarkers

BACKGROUND AND AIMS

Atrophic gastritis (AG) results most often from Helicobacter pylori (H. pylori) infection. AG is the most important single risk condition for gastric cancer that often leads to an acid-free or hypochlorhydric stomach. In the present paper, we suggest a rationale for noninvasive screening of AG with stomach-specific biomarkers.

METHODS

The paper summarizes a set of data on application of the biomarkers and describes how the test results could be interpreted in practice.

RESULTS

In AG of the gastric corpus and fundus, the plasma levels of pepsinogen I and/or the pepsinogen I/pepsinogen II ratio are always low. The fasting level of gastrin-17 is high in AG limited to the corpus and fundus, but low or non-elevated if the AG occurs in both antrum and corpus. A low fasting level of G-17 is a sign of antral AG or indicates high intragastric acidity. Differentiation between antral AG and high intragastric acidity can be done by assaying the plasma G-17 before and after protein stimulation, or before and after administration of the proton pump inhibitors (PPI). Amidated G-17 will rise if the antral mucosa is normal in structure. H. pylori antibodies are a reliable indicator of helicobacter infection, even in patients with AG and hypochlorhydria.

CONCLUSIONS

Stomach-specific biomarkers provide information about the stomach health and about the function of stomach mucosa and are a noninvasive tool for diagnosis and screening of AG and acid-free stomach.

Serum biomarkers provide an accurate method for diagnosis of atrophic gastritis in a general population: The Kalixanda study

OBJECTIVE

Serological biomarkers can be used for non-invasive diagnosis of gastritis and atrophic gastritis. The aim of this study was to compare the validity of serum levels of pepsinogen I (PGI) and II (PGII), gastrin-17 (G-17) and Helicobacter pylori antibodies (Hpab) with that of the gold standard histology for diagnosis of atrophic gastritis in a population sample from Northern Sweden.

MATERIAL AND METHODS

In all, 1000 subjects underwent endoscopies with biopsies. Serum biomarkers were available in 976 subjects for independent diagnosis of gastric mucosal status using a predetermined diagnostic algorithm.

RESULTS

Overall agreement between histology and serological biomarkers in diagnosing corpus atrophy was 96% (CI 95%: 95-97%). Sensitivity and specificity of markers for atrophic gastritis were 71% (CI 68-74%) and 98% (CI 97-99%) respectively, corresponding to 69% (CI 95%: 66-72%) and 98% (95% CI 97-99%) positive and negative predictive values. The positive likelihood ratio was 35.5 (95% CI: 35.0-36.0%). In subgroups with normal stomachs, H. pylori non-atrophic gastritis and H. pylori-negative gastritis by histology, the prevalence of corpus atrophy diagnosed with the biomarkers was 0.8% and 4.9%, respectively. In total, 6.6% of subjects in the study population had corpus atrophy according to the serological biomarkers. CONCLUSIONS. Serological biomarkers show a high degree of accuracy as a non-invasive method to diagnose corpus atrophy, which is common in the general population.

Do urea breath test (UBT) referrals for Helicobacter pylori testing match the clinical guidelines in primary care practice? A prospective observational study

BACKGROUND

Various international guidelines recommend the use of non-endoscopic tests [such as urea breath test (UBT)] for the evaluation of dyspeptic patients, unless endoscopy is clinically indicated.

AIM

To assess adherence with guidelines for UBT referrals among primary care doctors in Israel.

METHODS

Patients referred by primary care doctors to an open-access UBT service were included in the study. Prior to the test, all patients were administered with a short questionnaire regarding their symptoms, previous and concomitant medications including previous Helicobacter pylori eradication.

RESULTS

The study sample consisted of 209 patients, aged 18-94 years, M/F = 74/135. The UBT was judged to be appropriate in 94 (45%) subjects, inappropriate in 93 (44.5%) subjects and appropriate but avoidable in 22 (10.5%) subjects, most of them asymptomatic patients following anti H. pylori treatment. The inappropriate indications include 38 (18%) patients with suspected gastro-oesophageal reflux disease symptoms and 21 (10%) dyspeptic patients aged 45 years or more.

CONCLUSION

Nearly 45% percent of UBT referrals in primary care practice were inappropriate, and a significant number of dyspeptic patients should have been referred to endoscopy. These findings show a substantial non-compliance with guidelines for H. pylori testing among primary care doctors.

Urease-positive bacteria in the stomach induce a false-positive reaction in a urea breath test for diagnosis of Helicobacter pylori infection

This study investigated the influence of urease-positive non-Helicobacter pylori bacteria on the results of a urea breath test (UBT) to evaluate the diagnostic utility of a UBT using film-coated [(13)C]urea tablets. The UBT was performed in 102 patients treated with a proton pump inhibitor and antibiotics for the eradication of H. pylori. Urease-producing bacteria other than H. pylori were isolated and identified from the oral cavity and stomach. In 4/102 patients, the UBT gave false-positive results. These false-positive results were found to be caused by the presence of urease-positive bacteria in the oral cavity and stomach. Five bacterial species with urease activity (Proteus mirabilis, Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae and Staphylococcus aureus) were subsequently isolated from the oral cavity and/or stomach. As there was no correlation between the in vitro urease activity of urease-positive non-H. pylori bacteria and the UBT value, and all of the patients with a false-positive UBT result were suffering from atrophic gastritis, it is possible that the false-positive results in the UBT were a result of colonization of urease-positive bacteria and gastric hypochlorhydric conditions. Thus, for the diagnosis of H. pylori infection using a UBT, the influence of stomach bacteria must be considered when interpreting the results.

13C urea breath test for (Helicobacter pylori): determination of the optimal cut-off point in a Canadian community population

AIM

To determine the test characteristics and the optimal cut-off point for the (13)C urea breath test ((13)C UBT) in a Canadian community laboratory setting.

METHODS

Of 2232 patients (mean age +/- SD: 51+/-21 years, 56% female) who completed a (13)C UBT, 1209 were tested to evaluate the primary diagnosis of (Helicobacter pylori) infection and 1023 were tested for confirmation of eradication following treatment. Cluster analysis was performed on the (13)C UBT data to determine the optimal cut-off point and the risk of false-positive and false-negative results. Additionally, 176 patients underwent endoscopic biopsy to allow validation of the sensitivity and specificity of the (13)C UBT against histology and microbiology using the calculated cut-off point.

RESULTS

The calculated cut-off points were 3.09 delta/1000 for the whole study population (n=2232), 3.09 delta/1000 for the diagnosis group (n=1209) and 2.88 delta/1000 for the post-treatment group (n=1023). When replacing the calculated cut-off points by a practical cut-off point of 3.0 delta/1000, the risk of false-positive and false-negative results was lower than 2.3%. The (13)C UBT showed 100% sensitivity and 98.5% specificity compared with histology and microbiology (n=176) for the diagnosis of active (H pylori) infection.

CONCLUSIONS

The (13)C UBT is an accurate, noninvasive test for the diagnosis of (H pylori) infection and for confirmation of cure after eradication therapy. The present study confirms the validity of a cut-off point of 3.0 delta/1000 for the (13)C UBT when used in a large Canadian community population according to a standard protocol.

The 13carbon urea breath test for the diagnosis of Helicobacter pylori infection in subjects with atrophic gastritis: evaluation in a primary care setting

BACKGROUND

(13)Carbon urea breath testing is reliable to detect current infection with Helicobacter pylori but has been reported to be of limited value in selected patients with atrophic body gastritis or acid-lowering medication.

AIM

To evaluate the accuracy of (13)carbon urea breath testing for H. pylori detection in 20 asymptomatic patients with histologically confirmed atrophic body gastritis in a primary care setting.

METHODS

(13)Carbon urea breath testing and serology were compared with H. pylori culture of a corpus biopsy as reference test.

RESULTS

All tests were in agreement in 12 patients, being all positive in six and all negative in six. One patient was positive for serology and culture but negative for (13)carbon urea breath testing, five patients had only positive serology and two patients had only positive (13)carbon urea breath testing. (13)Carbon urea breath testing showed an accuracy with culture of 85% and anti-H. pylori serology with culture of 75%. (13)Carbon urea breath testing carried out in patients with positive serology showed an accuracy of 92%. Receiver operating characteristic curve analysis of (13)carbon urea breath testing shows optimal discrimination at the prescribed cut-off value.

CONCLUSIONS

(13)Carbon urea breath testing can be used as diagnostic H. pylori test in asymptomatic patients with atrophic body gastritis, preferably in addition to serology, to select subjects for anti-H. pylori therapy.

Influence of urease activity in the intestinal tract on the results of 13C-urea breath test

BACKGROUND AND AIM

A late rise in (13)CO2 excretion in the (13)C-urea breath test (UBT) should be found when the substrate passes rapidly through the stomach and makes contact with the colonic bacteria. The aim of this study was to evaluate the influence of intestinal urease activity on the results of the UBT.

METHOD

A total of 143 subjects who were diagnosed as Helicobacter pylori negative by serology, histology and rapid urease test were recruited. At the end of endoscopy, the tip of the endoscope was placed to the second part of the duodenum and 20 mL of water containing 100 mg of (13)C-urea was sprayed into the duodenum. Breath samples were taken at baseline and at 5, 10, 20, 30 and 60 min after administration.

RESULTS

Of 143 subjects, breath Delta(13)CO2 values higher than 2.5 per thousand were detected in six (4.2%), four (2.8%) and five (3.5%) subjects at 20, 30 and 60 min, respectively. There was no subject with high Delta(13)CO2 values at 5 and 10 min. Only one subject had an immediate rise at 60 min.

CONCLUSION

Variability derived from urease activity in the intestinal tract appears to be minimal up to 60 min after ingestion of the test urea.

Breath sample collection through the nostril reduces false-positive results of 13C-urea breath test for the diagnosis of helicobacter pylori infection

BACKGROUND

One of the disadvantages of '3C-urea breath test is possible interference by urease activity not related to Helicobacterpylori.

AIMS

We design the simple and non-invasive modification to avoid the contamination of 13CO(2) produced in the mouth.

PATIENTS AND METHODS

One hundred and twenty-nine patients who underwent diagnostic upper endoscopy were enrolled. Within 1 week of the endoscopic procedure, each patient received the modified 13C-urea breath test. Breath samples were collected at baseline and at 1, 3, 5, 10, 15, 20 and 30 min after ingestion of 100 mg 13C-urea solution through the mouth and the nostril at each time point.

RESULTS

The breath delta13CO2 value through the nostril at 1 min was already higher in H. pylori-positive patients than in H. pylori-negative patients. Using 2.5% as the cut-off value, the sensitivity and specificity of the modified 13C-urea breath test at 20 min were both 100%, whereas the sensitivity and specificity of the standard 13C-urea breath test were 97.7 and 94%, respectively, using 3% as the cut-off value.

CONCLUSIONS

The modified 13C-urea breath test in which breath samples are collected through the nostril provides an easy way of avoiding false-positive results for the detection of H. pylori infection.

Application of Maastricht 2-2000 guidelines for the management of Helicobacter pylori among specialists and primary care physicians in israel: are we missing the malignant potential of Helicobacter pylori?

BACKGROUND

The Maastricht 2-2000 guidelines on the current management of Helicobacter pylori infection were recently adopted by the Israeli Gastroenterological Association.

GOAL

To determine the impact of these clinical guidelines on the current knowledge, attitudes, and management of H. pylori among primary care physicians, hospital internists, and gastroenterologists in Israel.

STUDY

Self-administered, voluntary, anonymous questionnaires were given personally to 229 physicians, 73 primary care physicians, 71 internists, and 85 gastroenterologists. The questions evaluated 4 main issues in the management of H. pylori: (1). the optimal diagnostic test, (2). indications for eradication, (3). combination and duration of triple therapy, and (4). the need for confirmation following eradication.

RESULTS

There were significant variations in the adherence of those recommendations among gastroenterologists, internists, and primary care physicians. Specifically, 94.1% of gastroenterologists and 88.9% of internists consider the urea breath test the test of choice for H. pylori diagnosis compared with 60.0% of the primary care physicians. Significant differences in the eradication indications for mucosa-associated lymphoid tissue (MALT) lymphoma, first-degree relatives of gastric cancer patients, atrophic gastritis, functional dyspepsia, and concomitant use of nonsteroidal antiinflammatory drugs were demonstrated among gastroenterologists and the other groups.

CONCLUSIONS

Primary care physicians may not be aware of important indications for diagnosis and eradication of H. pylori related to the risk of gastric malignancy or concomitant use of nonsteroidal antiinflammatory drugs. Public health agencies may need to increase penetration of the Maastricht 2000 recommendations to primary care physicians.