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

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.

Postoperative bleeding risk after gastric endoscopic submucosal dissection during antithrombotic drug therapy

BACKGROUND AND AIM

The safety of gastric endoscopic submucosal dissection (ESD) in the antithrombotic drug users remains controversial.

METHODS

Patients who underwent gastric ESD at Okayama University Hospital between March 2006 and February 2016 were enrolled. This study investigated the risk of post-ESD bleeding according to the management of the antithrombotic drugs.

RESULTS

One thousand twenty lesions (872 patients) were enrolled. In a multivariate analysis, heparin replacement (odds ratio [OR] 5.0, 95% confidence interval [CI] 1.8-14), multiple antithrombotic drug use (OR 2.9, 95% CI 1.1-6.9), a resected specimen of ≥ 33 mm in diameter (OR 2.7, 95% CI 1.5-5.4), Helicobacter pylori negativity (OR 2.2, 95% CI 1.3-3.7), and tumors located in the lower third of the stomach (OR 1.7, 95% CI 1.0-2.9) were significant risk factors for post-ESD bleeding, while the continuation of aspirin or cilostazol was not (OR 2.6, 95% CI 0.72-7.8). The bleeding rate of the continuation group was comparable with that of the all cessation group among single antithrombotic drug users (4.5% vs 4.4%, P = 1.0); however, the rate of the continuation group was significantly higher than that of the all cessation group among multiple antithrombotic drug users (67% vs 15%, P = 0.020).

CONCLUSIONS

The risk of post-ESD bleeding differed according to the management of the antithrombotic drugs. The gastric ESD under the cessation or continuation of aspirin or cilostazol monotherapy was acceptable. However, multiple antithrombotic drug use or heparin replacement was associated with a higher risk of post-ESD bleeding.

Does Helicobacter pylori Exacerbate Gastric Mucosal Injury in Users of Nonsteroidal Anti-Inflammatory Drugs? A Multicenter, Retrospective, Case-Control Study

Background/Aims

The interaction between nonsteroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori remains controversial. We retrospectively investigated whether H. pylori infection exacerbates severe gastric mucosal injury among chronic NSAID users.

Methods

From January 2010 to December 2013, a total of 245 long-term NSAID (including low-dose aspirin) users who had undergone an esophagogastroduodenoscopy and had been evaluated for H. pylori infection were enrolled at Okayama University Hospital and Tsuyama Chuo Hospital. The degree of gastric mucosal injury was assessed according to the modified Lanza score (MLS). Severe gastric mucosal injury was defined as an MLS ≥4. Univariate and multivariate logistic regression analyses were performed.

Results

In the univariate analysis, age ≥75 years (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3 to 4.2), H. pylori-positivity (OR, 2.0; 95% CI, 1.2 to 3.5), and the concomitant use of proton pump inhibitors (PPIs) (OR, 0.48; 95% CI, 0.26 to 0.86) were significantly associated with severe gastric mucosal injury. The multivariate analysis was adjusted by age and sex and demonstrated that H. pylori-positivity (OR, 1.8; 95% CI, 1.0 to 3.3) and the concomitant use of PPIs (OR, 0.53; 95% CI, 0.28 to 0.99) significantly contributed to severe gastric mucosal injury.

Conclusions

H. pylori infection exacerbates severe gastric mucosal injury among chronic NSAID users.

Efficacy of a quadruple therapy regimen for Helicobacter pylori eradication after partial gastrectomy

We aimed to evaluate the effectiveness and safety of bismuth-containing quadruple therapy plus postural change after dosing for Helicobacter pylori eradication in gastrectomized patients. We compared 76 gastric stump patients with H. pylori infection (GS group) with 50 non-gastrectomized H. pylori-positive patients who met the treatment indication (controls). The GS group was divided into GS group 1 and GS group 2. All groups were administered bismuth potassium citrate (220 mg), esomeprazole (20 mg), amoxicillin (1.0 g), and furazolidone (100 mg) twice daily for 14 days. GS group 1 maintained a left lateral horizontal position for 30 min after dosing. H. pylori was detected using rapid urease testing and histologic examination of gastric mucosa before and 3 months after therapy. Mucosal histologic manifestations were evaluated using visual analog scales of the updated Sydney System. GS group 1 had a higher prevalence of eradication than the GS group 2 (intention-to-treat [ITT]: P=0.025; per-protocol [PP]: P=0.030), and the control group had a similar prevalence. GS group 2 had a lower prevalence of eradication than controls (ITT: P=0.006; PP: P=0.626). Scores for chronic inflammation and activity declined significantly (P<0.001) 3 months after treatment, whereas those for atrophy and intestinal metaplasia showed no significant change. Prevalence of adverse reactions was similar among groups during therapy (P=0.939). A bismuth-containing quadruple therapy regimen plus postural change after dosing appears to be a relatively safe, effective, economical, and practical method for H. pylori eradication in gastrectomized patients.

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.

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.

Physiological evaluation of residual stomach motility after local resection in conscious dogs

PURPOSE

To investigate the phenomenon of remnant gastric motility and emptying after local resection.

METHODS

Fifteen dogs were divided into three groups: a control (CONT) group, a group that underwent local resection of the greater (GREAT) curvature, and a group that underwent resection of the lesser (LESS) curvature. We conducted a strain gauge force transducer study, a [(13)C]octanoic acid breath test ((13)C-OBT), and a mosapride citrate effect test. Based on these results, we worked out the receptive relaxation (RR), motility index (MI), and postprandial period (PP) in the postprandial state, and the frequency, duration, and MI of phase III in the fasted state. The half emptying time (T (1/2)) of (13)C-OBT was also calculated. The MI was compared according to the mosapride effect test results.

RESULTS

Postprandial RR, antro-pyloro-duodenal coordination, and fasting contractions were maintained in all three groups. Receptive relaxation was significantly shorter in the LESS group than in the other groups. Motility index was significantly lower in both treatment groups than in the CONT group. The PP was significantly longer in the GREAT group than in the other two groups. The (13)CO(2) excretion curves did not differ significantly among the groups. The duration of phase III was remarkably less in the treatment groups than in the CONT group, and MI was significantly lower in the LESS group than in the other groups in the fasted state. The MI increased remarkably after mosapride administration in the CONT group, showing no differences in other objective groups.

CONCLUSION

Gastric function was maintained after gastric local resection, although its motility decreased.

Diagnostic value of rapid urease test and urea breath test for Helicobacter pylori detection in patients with Billroth II gastrectomy: a prospective controlled trial

AIM

The aim of this work was to assess the reliability of rapid urease test (RUT) and urea breath test (UBT) for detecting Helicobacter pylori (H. pylori) in patients with Billroth II (BII) gastrectomy, using histology as reference.

METHODS

In this prospective controlled study, 31 consecutive patients with BII gastrectomy and 73 controls who had an indication for endoscopy were included. Their H. pylori status was assessed with biopsies for histology, RUT and UBT. Histology served as the gold standard. Only the biopsies from the gastric fundus were evaluated. Specificity, sensitivity, positive and negative predictive value, degree of agreement and k-statistics were used.

RESULTS

RUT and UBT for detecting H. pylori in the control group had excellent agreement [97%, kappa (k)=0.94 and 99%, k=0.97 respectively] with biopsies. In BII patients, RUT from fundic biopsies had very good agreement (87%, k=0.74) compared to histology from fundic biopsies, whereas the UBT was unreliable (agreement: 71%, k=0.41) compared to histology.

CONCLUSION

The RUT from fundic biopsies in BII patients is a reliable test for H. pylori detection, whereas the UBT is unreliable.

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.

An optimized 13C-urea breath test for the diagnosis of H pylori infection

AIM: To validate an optimized 13C-urea breath test (¹³C-UBT) protocol for the diagnosis of H pylori infection that is cost-efficient and maintains excellent diagnostic accuracy.

METHODS: 70 healthy volunteers were tested with two simplified ¹³C-UBT protocols, with test meal (Protocol 2) and without test meal (Protocol 1). Breath samples were collected at 10, 20 and 30 min after ingestion of 50 mg ¹³C-urea dissolved in 10 mL of water, taken as a single swallow, followed by 200 mL of water (pH 6.0) and a circular motion around the waistline to homogenize the urea solution. Performance of both protocols was analyzed at various cut-off values. Results were validated against the European protocol.

RESULTS: According to the reference protocol, 65.7% individuals were positive for H pylori infection and 34.3% were negative. There were no significant differences in the ability of both protocols to correctly identify positive and negative H pylori individuals. However, only Protocol 1 with no test meal achieved accuracy, sensitivity, specificity, positive and negative predictive values of 100%. The highest values achieved by Protocol 2 were 98.57%, 97.83%, 100%, 100% and 100%, respectively.

CONCLUSION: A 10 min, 50 mg ¹³C-UBT with no test meal using a cut-off value of 2-2.5 is a highly accurate test for the diagnosis of H pylori infection at a reduced cost.

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.

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.

Diagnosis of Helicobacter pylori infection

Numerous studies are still published on diagnostic tests for Helicobacter pylori, essentially for noninvasive tests. The urea breath test is applied in different types of patients, and there are attempts to have quicker and simpler protocols. Stool tests using monoclonal antibodies are now evaluated while serology is still a subject of interest. The progress in PCR (multiplex PCR, real-time PCR) has also stimulated the research in this area of invasive tests, in order to get insight into virulence factors, macrolide susceptibility and to detect H. pylori in nonconventional specimens.

Review article: diagnosis and treatment of Helicobacter: a 2002 updated review

The year 2002 saw advances on many fronts in the study of Helicobacter and gastroduodenal disease. Several studies have confirmed endoscopy as a valuable management procedure with confirmation of the diagnostic utility of the rapid urease test and the description of a new formulation of the test, which is more rapid in giving a result. Serology has been re-confirmed as a useful investigation in selected populations. Some commercial kits for near patient testing have also been assessed and although generally regarded as less accurate than laboratory based tests some have shown acceptable accuracy. The recent exciting development in diagnostic serology is the availability of the faecal antigen test; further studies have confirmed its usefulness as recommended screening tests. There have been several studies demonstrating that a test and treat policy has a significant patient benefit, both economic and medical, although there is some doubt if eradication of Helicobacter leads to regression of atrophy and metaplasia. However, in low Helicobacter-prevalence areas the test and treat policy is being challenged as an effective management strategy. Further studies have shown that compliance with treatment regimens is an important determinant of successful eradication. Finally several new eradication regimens have been reported particularly for use in patients who have had previous unsuccessful eradication attempts.