Usefulness of the [13C]-urea breath test for detection of Helicobacter pylori infection in fasting patients

Effect of Citric Acid on Accuracy of 13C-Urea Breath Test after Helicobacter pylori Eradication Therapy in a Region with a High Prevalence of Atrophic Gastritis

Background/Aims

The validity of ¹³C-urea breath test (¹³C-UBT) for Helicobacter pylori detection is influenced by atrophic gastritis. The aim of this study was to evaluate the effect of citric acid on the accuracy of ¹³C-Urea breath test after H. pylori eradication therapy in a region where atrophic gastritis is common.

Methods

In this prospective study, H. pylori-positive patients received ¹³C-UBT after H. pylori eradication regimen. They were classified into citric acid group and control group. To determine diagnostic accuracy of ¹³C-UBT, patients were offered invasive methods.

Results

A total of 1,207 who successfully took H. pylori-eradication regimen received UBT. They were assigned into the citric acid group (n=562) and the control group (n=645). The mean ¹³C-UBT value of the citric acid group was 10.3±26.4‰, which was significantly (p<0.001) higher than that of that control group (5.1‰±12.6‰). Of these patients 122 patients were evaluated by endoscopic biopsy methods. Based on invasive tests, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of ¹³C-UBT for the citric acid group were 83.3%, 91.7%, 81.3%, 55.0%, and 97.5%, respectively. Those of the control group were 87.7%, 90.9%, 88.2%, 62.5%, and 97.8%, respectively. They were not significantly different between the two groups. Although the presence of gastric atrophy and intestinal metaplasia (IM) decreased the accuracy, the decrease was not significant.

Conclusions

In a country with high prevalence of atrophic gastritis or IM, false positivity remained common despite the use of citric acid in ¹³C-UBT.

Comparison of the detection of Helicobacter pylori infection by commercially available serological testing kits and the 13C-urea breath test

BACKGROUND

Serum Helicobacter pylori (H. pylori) antibody kits (LZ and LIA) using the latex agglutination immunoassay method are commercially available, but few studies have been performed to determine their diagnostic accuracy or to compare their results with those of enzyme-linked immunosorbent assay (ELISA) kits (EP and EIA).

METHODS

Sera were obtained from 213 hospital outpatients with dyspeptic symptoms. The serological results were compared with the result of the ¹³C-urea breath test (UBT) which seems to be reliable.

RESULTS

Of the 213 subjects, 154 were diagnosed as positive for H. pylori infection according to the UBT. The sensitivities and specificities of these tests were 97.4% and 76.3%, 98.1% and 78.0%, 99.4% and 74.6%, and 98.1% and 71.2% for the EP, LZ, EIA and LIA tests, respectively. When the 13 subjects whose seropositive results of the four kits were completely opposite to the negative results of the UBT were excluded, the specificities of evaluated kits were all higher than 90%. The concordance rate between the EP and EIA tests was 98.1% (Spearman's rank correlation coefficient = 0.83) and that between the LZ and LIA tests was 97.1% (correlation coefficient = 0.91). The LZ gave higher antibody titer value than EP (p < 0.0001, Z = 9.82; Wilcoxon signed-rank test), and EIA gave higher value than LIA (p < 0.0001, Z = 6.43; Wilcoxon signed-rank test).

CONCLUSIONS

The latex immunoassay method provided the same reliability to ELISA in terms of the diagnostic accuracy for current H. pylori infection, although we should take into account the titer value differences by each test method in practical use.

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.

Effect of Helicobacter pylori infection on iron absorption in asymptomatic adults consuming wheat flour fortified with iron and zinc

Helicobacter pylori infection could impair iron absorption from fortified products. The objective of the study was to determine the effect of H. pylori infection on iron absorption from asymptomatic adults consuming wheat flour fortified with iron and zinc. The (13)C urea breath test was used to assess H. pylori infection. Twenty-four H. pylori-positive and 26 H. pylori-negative volunteers completed the study. On day 1, the subjects were randomized to receive for breakfast bread fortified with either ferrous sulfate and zinc sulfate or ferrous fumarate and zinc oxide. Bread fortified with ferrous sulfate was labeled with (59)Fe as sulfate, and bread fortified with ferrous fumarate was labeled with (55)Fe as fumarate. On day 3, they received the other type of bread, with the respective tracers. On days 18-23, a proton pump inhibitor was administered to all subjects. On day 24, all subjects received bread fortified with ferrous fumarate and zinc oxide labeled with (55)Fe as fumarate. H. pylori prevalence was 77.6%. The geometric mean (±1 SD) of iron absorption was significantly higher for ferrous sulfate than fumarate (6.9 ± 2.9% vs. 0.5 ± 3.5%, p < 0.001). The H. pylori-negative subjects absorbed significantly more iron from bread fortified with either ferrous sulfate (10.5 ± 3.1% vs. 4.4 ± 2.2%, p < 0.001) or ferrous fumarate (0.6 ± 3.9% vs. 0.4 ± 3.1%, p < 0.001). Iron absorption was not significantly different between groups after administration of a proton pump inhibitor (0.3 ± 3.3% vs. 0.3 ± 2.7%, p = 0.11). H. pylori infection has a negative effect on iron absorption in asymptomatic adults consuming iron- and zinc-fortified wheat flour.

Lack of diagnostic accuracy of the monoclonal stool antigen test for detection of Helicobacter pylori infection in young Australian aboriginal children

BACKGROUND

: The prevalence of Helicobacter pylori infection among Aboriginal Australians children is unclear. The aims of the present study are to determine the prevalence of H. pylori infection among young Aboriginal children recovering from acute diarrheal disease in hospital and to evaluate the H. pylori stool antigen test as a noninvasive diagnostic test in this setting.

METHODS

: This was a prospective comparative study using the C-Urea Breath Test as reference standard. Fifty-two children between 4 months and 2 years of age were consecutively enrolled. These children comprised a representative sample of Australian Aboriginal children admitted to hospital with acute diarrheal disease from remote and rural communities across Northern Territory of Australia.

RESULTS

: The overall prevalence of H. pylori was 44.2%. The stool antigen test had a sensitivity of 0.55 (95% confidence interval [CI]: 0.35-0.73) with a positive predictive value of 0.65 (95% CI: 0.42-0.82). The specificity was 0.68 (95% CI: 0.46-0.84) with a negative predictive value of 0.58 (95% CI: 0.39-0.75). Analysis of receiver operator characteristic curve yielded an overall accuracy of the stool antigen test of 61% (48%-75%).

CONCLUSIONS

: The prevalence of H. pylori infection among very young Aboriginal children from remote and rural communities was high and consistent with early acquisition. The diagnostic accuracy of the stool antigen test to diagnose H. pylori in this setting was poor.

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.

[Breath tests in the diagnosis of gastrointestinal diseases]

Determination of carbon or hydrogen markers in breath has allowed closer investigation of the pathogenic mechanisms of several gastrointestinal diseases. Thus, the 13C-urea breath test is a nonaggressive, simple and safe test with excellent accuracy both in the initial diagnosis of Helicobacter pylori infection and in confirmation of its eradication following treatment. Moreover, because of the simplicity, reproducibility and safety of these types of procedure, they have tended to substitute more uncomfortable and expensive techniques that were traditionally used in gastroenterology. Several breath tests have been developed that allow reliable evaluation of liver or exocrine pancreatic function, gastrointestinal motility, as related to gastric emptying or orocecal transit time, and a diagnostic approach to clinical problems that could be due to bacterial overgrowth or malabsorption of various sugars.

Review article: 13C-urea breath test in the diagnosis of Helicobacter pylori infection -- a critical review

The urea breath test is a non-invasive, simple and safe test which provides excellent accuracy both for the initial diagnosis of Helicobacter pylori infection and for the confirmation of its eradication after treatment. Some studies have found no differences between urea breath test performed under non-fasting conditions. The simplicity, good tolerance and economy of the citric acid test meal probably make its systematic use advisable. The urea breath test protocol may be performed with relatively low doses (<100 mg) of urea: 75 mg or even 50 mg seem to be sufficient. With the most widely used protocol (with citric acid and 75 mg of urea), excellent accuracy is obtained when breath samples are collected as early as 10-15 min after urea ingestion. A unique and generally proposed cut-off level is not possible because it has to be adapted to different factors, such as the test meal, the dose and type of urea, or the pre-/post-treatment setting. Fortunately, because positive and negative urea breath test results tend to cluster outside of the range between 2 and 5 per thousand, a change in cut-off value within this range would be expected to have little effect on clinical accuracy of the test.

Urine-based enzyme-linked immunosorbent assay for the detection of Helicobacter pylori antibodies in children

OBJECTIVE

Recent studies of urine-based enzyme-linked immunosorbent assays (ELISA) for detection of antibody to Helicobacter pylori (H. pylori) have already shown high sensitivity and specificity in adults. The diagnostic accuracy of these assays in children was investigated.

METHODS

The results of serum and urine-based ELISAs were compared with those of 13C-urea breath tests (13C-UBT) and/or detection of faecal H. pylori antigen in 68 children. The effect of urine total immunoglobulin G (IgG) levels on the ELISA results for anti-H. pylori antibodies in urine was also examined.

RESULTS

The sensitivity, specificity and accuracy of the serum ELISA were 72.7%, 96.3%, and 92.3% respectively, while those of the urine-based ELISA were 92.3%, 76.4%, and 79.4% respectively. The level of urine total IgG in children with false-positive results in the urine-based ELISA, was significantly higher than that in children who showed negative results in both the urine-based ELISA and the 13C-UBT and/or faecal H. pylori antigen tests. Human gamma-globulin affected the urine-based ELISA results at final concentrations of 2.0 mg/dL, 3.0 mg/dL, and 4.0 mg/dL; the anti-H. pylori antibody values were significantly higher than the ELISA values without the addition of human gamma-globulin.

CONCLUSION

The findings suggested that the specificity of urine-based ELISA for detection of H. pylori antibodies is low in children, since high urinary levels of total IgG increase the likelihood of false-positive results.

Diagnostic accuracy of serological kits for Helicobacter pylori infection with the same assay system but different antigens in a Japanese patient population

Helicobacter pylori infection is thought to be a causal risk factor for gastric carcinoma. Recently, diagnostic accuracy of serological kits for H. pylori infection that were made in Western countries has been reported to be lower when used among Oriental populations. Diagnostic accuracy of two serological kits [HM-CAP and HM-CAP with antigens extracted from clinically isolated Japanese H. pylori strains (J-HM-CAP)] was investigated in 440 samples from a Japanese patient population by using the (13)C-urea breath test as gold standard. According to the original optimal cut-off value, HM-CAP provided 87.5 % sensitivity and 84.8 % specificity with 86.8 % accuracy and J-HM-CAP provided 95.5 % sensitivity and 81.9 % specificity with 92.3 % accuracy. This study suggests that antigens from HM-CAP are satisfactory for examining a Japanese patient population, but that using local antigens improves accuracy.

Is antimicrobial susceptibility testing necessary before second-line treatment for Helicobacter pylori infection?

BACKGROUND

An antimicrobial susceptibility test for Helicobacter pylori before second-line treatment is often performed, although whether the test is truly necessary remains unknown.

PATIENTS AND METHODS

Eighty-two patients with H. pylori infection for whom first-line treatment with a 1-week proton pump inhibitor/amoxicillin-clarithromycin (AC) regimen had failed were randomly assigned to two groups: those having or not having the susceptibility test before re-treatment. The cure rates for these two groups were compared.

RESULTS

Five of the 82 patients were excluded from the analysis. For 38 patients in the susceptibility-test group, we used what we considered the best regimen based on susceptibility testing: 10 patients [no resistance to clarithromycin (CAM)] received the lansoprazole-amoxicillin-clarithromycin regimen, 22 patients [19 CAM resistant, metronidazole (MNZ) susceptible; three failure of culture] were given the lansoprazole-amoxicillin-metronidazole (LAM) regimen, and six patients (both MNZ and CAM resistant) received dual therapy with omeprazole (OPZ) and amoxicillin (AMOX) in which the OPZ dose was determined by the CYP2C19 gene polymorphism. For 39 patients in the group with no susceptibility testing, LAM regimens were prescribed. The intention-to-treat (ITT)-based cure rates in the groups with and without susceptibility testing were 81.6% (95% confidence interval; 66-92%) and 92.4% (79-98%), respectively, and there was no significant difference between these two groups.

CONCLUSION

Susceptibility testing is not necessarily required before second-line therapy if the first-line treatment has been performed using proton pump inhibitor/AC regimens.

[13C]-urea breath test without prior fasting and without test meal is accurate for the detection of Helicobacter pylori infection in Chinese

BACKGROUND AND AIM

Conventional [13C]-urea breath test ([13C]-UBT) requires prior fasting and a test meal, which theoretically improves the accuracy of the test. However, recent studies have suggested that prior fasting and test meal may not be essential. We aimed to determine the accuracy of a new [13C]-UBT protocol without fasting in Chinese.

METHODS

Dyspeptic patients referred for upper endoscopy were recruited. The gold standard for Helicobacter pylori infection was the combination of Campylobacter-like organism (CLO) test and histology. Group I (n = 213) patients underwent [13C]-UBT with prior fasting and with citrate acid test meal. Group II (n = 123) patients underwent [13C]-UBT without prior fasting but with test meal. Group III (n = 90) patients underwent [13C]-UBT without prior fasting and without test meal.

RESULTS

The highest accuracy for groups I, II and III was 96.7, 95.1 and 95.5% using a cut-off value of 5.0, 5.5 and 3.5, respectively. The sensitivities and specificities were 97.4 and 95.8% in group I, 93.3 and 96.8% in group II, and 96.5 and 93.9% in group III, respectively.

CONCLUSION

The [13C]-UBT protocols without prior fasting and either with or without test meal produce highly accurate and reliable results in the Chinese population.

Improvement of reflux symptoms 3 years after cure of Helicobacter pylori infection: a case-controlled study in the Japanese population

BACKGROUND

Development of reflux esophagitis is one of the adverse effects that cause concern in relation to curative treatment of Helicobacter pylori infection. However, recent studies present a rather negative association between curative treatment and development of reflux esophagitis or reflux symptoms. Therefore, this issue has remained controversial. Accordingly, we investigated the long-term adverse effects of H. pylori eradication treatment in special reference to development of reflux symptoms.

PATIENTS AND METHODS

We conducted a case controlled study by mailing structured questionnaires on past (before curative treatment or 3 years previously) and current status. A case was an endoscopically confirmed peptic ulcer patient with confirmed cure of the infection after eradication treatment 3 years previously and a control was one who had not undergone the eradication treatment during the same period. We studied 241 pairs who matched for age, gender, and type of ulcer disease (GU, DU or GDU). Of these pairs, 81.3% were male and the mean age was 52.6 +/- 9.6 year (range 23-76).

RESULTS

The rates of patients with improved reflux symptoms in the case and control groups were 65.4% and 30.4%, respectively, with the rate being significantly greater in the case group. On the contrary, the rates of those with worsened reflux symptoms were similar (5.1% and 7.6%). Regarding general events, the rate of patients with decreased frequency of hospital visits and of those who regularly used antiacid medications were significantly decreased in the case group. Furthermore, the case group experienced significantly fewer hospital admissions for various diseases in this 3-year period. However, a significantly greater number of case group patients than control subjects gained weight.

CONCLUSION

Reflux symptoms as well as general well-being were significantly improved after cure of H. pylori infection.

Evaluation of the Helicobacter pylori stool antigen test for monitoring eradication therapy

OBJECTIVE

We aimed to clarify the time course of the Helicobacter pylori stool antigen (HpSA) level during and after eradication therapy and to determine the appropriate time of measurement of HpSA to evaluate eradication.

METHODS

The subjects were 47 patients who were positive for H. pylori. The patients underwent a 1-wk regimen of triple therapy. The outcome of the eradication therapy was judged by urea breath test, culture, and histology 6 wk after the end of treatment. The HpSA level was serially measured nine times from before therapy until 12 wk after the end of therapy.

RESULTS

In the group with successful eradication, HpSA became negative immediately after the end of therapy and the negativity persisted. In contrast, in the noneradication group HpSA became negative immediately after therapy, but became positive again within 2 wk after the end of therapy. The mean absorbance value of the HpSA test on the 4th day after the initiation of eradication therapy was significantly higher in the noneradication group than in the group with successful eradication. The diagnostic accuracy of the HpSA test increased to > or = 90% 2 wk after therapy and thereafter. Comparison of the diagnostic accuracy at 4 wk after the end of therapy showed no significant differences with that at 2, 6, 8, and 12 wk after the end of therapy.

CONCLUSIONS

The course of the HpSA levels during and after eradication therapy in patients with successful eradication was quite different from that in noneradication patients. Measurement of HpSA was useful to evaluate eradication, and the appropriate evaluation of the outcome of treatment could be made as early as 2 wk after the end of therapy.

Twenty-minute 50 mg 13C-urea breath test without test meal for the diagnosis of Helicobacter pylori infection in Chinese

BACKGROUND

We have previously shown that the 75 mg 13C-urea breath test without citrate test meal is highly accurate for the diagnosis of Helicobacter pylori infection in Chinese subjects. A lower dose 50 mg 13C-urea breath test protocol with a sampling time at 20 min has not been validated previously.

AIM

To investigate the accuracy of a 20-min 50 mg 13C-urea breath test protocol in Chinese subjects.

METHODS

Consecutive dyspeptic patients referred for upper endoscopy were recruited. 13C-urea breath test was performed using (a) 75 mg and 50 mg of 13C-urea on two separate days without a test meal, and (b) 50 mg of 13C-urea with 2.4 g citrate as test meal, and compared with the gold standard [rapid urease test (CLO test) and histology]. Baseline, 20-min and 30-min breath samples were collected in all cases.

RESULTS

Two hundred and six patients were tested. The accuracy of the 50 mg 13C-urea breath test (no citrate) at 20 min and 30 min was 98%, comparable to that of the 50 mg 13C-urea breath test with citrate (99.1%) and the 75 mg 13C-urea breath test without citrate (100%).

CONCLUSIONS

A 20-min 50 mg 13C-urea breath test without citrate produced highly accurate results for the diagnosis of Helicobacter pylori infection and is more economical and convenient for the Chinese population.

Strategy for retreatment of therapeutic failure of eradication of Helicobacter pylori infection

BACKGROUND AND AIM

A proton pump inhibitor (PPI)-based triple therapy consisting of a PPI, amoxicillin (A) and clarithromycin (C) or metronidazole (M) provides an eradication rate ranging from 80 to 90%. However, there have been few controlled studies with regard to the most effective regimen to re-treat patients after failure of the first-line therapy. Accordingly, we retrospectively reviewed our experiences and compared regimens with different combinations of antimicrobials to determine the optimal retreatment regimen.

METHODS

Out of 133 patients who had received second-line therapy after failure of first-line PPI/AC therapy, we selected, for review, patients who took the prescribed drugs for first-line therapy equal to, or more than 80%. As a result, data on 114 patients (83 males and 31 females; mean age 49.1 +/- 13.0 years; peptic ulcer n = 89; non-ulcer dyspepsia, n = 25) were eligible for evaluation. They had either repeated the PPI/AC regimen (n = 34; 5-14 days), or had been administered the PPI/AM regimen (n = 80; 10 days). The cure rates of the two regimens were compared.

RESULTS

The eradication rates for second-line therapy with the PPI/AC regimen versus the PPI/AM regimen were 52.9% (95% CI, 35-70) versus 81.3% (95% CI, 71-89) by intention-to-treat analysis (P < 0.01), and 62.1% (95% CI, 42-79) versus 91.4% (95% CI, 81-97) by per-protocol analysis (P < 0.01).

CONCLUSION

The eradication rate for the PPI/AM retreatment regimen was significantly higher than for the repeated PPI/AC regimen, suggesting that a 10-day PPI/AM regimen can be recommended as a retreatment regimen for patients who had first-line eradication therapy by PPI/AC regimens.

Simplified 13C-urea breath test for detection of Helicobacter pylori infection

OBJECTIVE

The U.S. standard 13C-urea breath test (13C-UBT) has proven to be extremely reliable but entails several complicated performance requirements and a test period of approximately 1 h. The aim of this study was to compare the standard 13C-UBT with a simplified version embodying modifications of test meal, duration of fasting, amount of 13C-urea, method of breath collection, and duration of test.

METHODS

This was a randomized, three-way, crossover study of the standard U.S. 13C-UBT, which contains 125 mg of 13C-urea and a pudding test meal. The final breath sample is taken 30 min after urea ingestion. This test was compared with a formulation containing 75 mg of 13C-urea, a 2.5-g citric acid test meal (UBT-Lite), and a final breath sample taken by direct exhalation into tubes 15 min after urea ingestion. We also compared the effect of prior meals versus fasting on the test outcome with the UBT-Lite.

RESULTS

A total of 259 subjects were enrolled in the trial, and 249 completed all three urea breath tests. There was excellent agreement between the three versions of the UBT with >98% of subjects having concordant results. Using predetermined criteria, there was substantial equivalence between the tests. Neither solid and/or liquid food up to 1 h before performing the UBT-Lite affected outcome.

CONCLUSION

The UBT-Lite formulation of the 13C-UBT proved to be an improved version of the U.S. standard 13C-UBT offering less expensive ingredients, shorter test duration, and a simplified breath test collection method, without sacrificing accuracy.

Five-day proton pump inhibitor-based quadruple therapy regimen is more effective than 7-day triple therapy regimen for Helicobacter pylori infection

BACKGROUND

There have been no reports that describe whether 5-day quadruple therapy (rabeprazole + amoxicillin + clarithromycin + metronidazole; RACM) could substitute for standard 7-day triple therapy as a first-line therapy for Helicobacter pylori.

PATIENTS AND METHODS

This study was designed as a randomized prospective single centre study. A total of 160 H. pylori-positive patients who had not received therapy were given either a 5-day RACM regimen (n=80, rabeprazole 20 mg b.d., amoxicillin 750 mg b.d., clarithromycin 200 mg b.d. and metronidazole 250 mg b.d.) or a 7-day RAC regimen (n=80, rabeprazole 20 mg b.d., amoxicillin 750 mg b.d. and clarithromycin 200 mg b.d.). Cure of the infection was assessed by a (13)C urea breath test 1 month after the completion of therapy.

RESULTS

The eradication rates of the 5-day RACM regimen and the 7-day RAC regimen were 93% (95% CI: 84--97%) and 81% (95% CI: 71--89%) by intention-to-treat analysis, 94% (95% CI: 86--98%) and 83% (95% CI: 73--91%) by all-patients-treated analysis analysis and 95% (95% CI: 87--98%; P < 0.05) and 82% (95% CI: 72--90%) by per protocol analysis, respectively. No serious adverse effect was observed, and 99% of the patients reported complete compliance.

CONCLUSIONS

The cure rate of the 5-day RACM regimen was more effective than the 7-day RAC regimen, suggesting that this regimen could be preferable as a first-line therapy for H. pylori infection.

On-site diagnosis of H. pylori infection by urine

We have recently developed an on-site diagnostic kit for H. pylori infection using urine (utilizing immunochromatographic method employing a nitrocellulose membrane coated by extracted H. pylori antigen). Accordingly, we investigated its usefulness in 155 consecutive dyspeptic patients using the 13C urea breath test as a gold standard and further compared its performance with two commercially available rapid diagnostic kits that use whole blood (Helisal Rapid Blood, and ImmunoCard H. pylori). As the results, the urine based on-site diagnostic kit provided 95.9% sensitivity and 87.9% specificity with 92.9% accuracy, which were comparable or even better than that of both rapid whole blood tests, suggesting its usefulness in screening of H. pylori infection.

5-day vs. 7-day triple therapy with rabeprazole, clarithromycin and amoxicillin for Helicobacter pylori eradication

AIM

To determine whether a 5-day regimen with rabeprazole, clarithromycin and amoxicillin (RCA) was as effective as a 7-day regimen.

METHODS

A total of 139 H. pylori-infected patients were randomized to receive either a 5-day or 7-day course of rabeprazole 10 mg b.d., clarithromycin 400 mg b.d. and amoxicillin 750 mg b.d. Eradication was assessed by CLO test, histology and 13C-urea breath test.

RESULTS

On the intention-to-treat basis, eradication rates were 66% (46 out of 70) and 84% (58 out of 69) for the 5- and 7-day regimens, respectively (P < 0.05). Using per protocol analysis, eradication rates were 70% (46 out of 66) and 91% (58 out of 64) for the 5- and 7-day regimens, respectively (P < 0.01). Adverse events, which were observed in 14 patients from each group, caused discontinuation of treatment in only two patients, resulting in excellent compliance.

CONCLUSIONS

Our 5-day regimen of RCA yielded inferior results, whereas the 7-day regimen achieved an eradication rate exceeding 90% on the per protocol basis. Therefore, treatment regimens of less than 7 days for proton pump inhibitor-clarithromycin-amoxicillin therapies cannot be recommended.

(13)C-urea breath test without a test meal is highly accurate for the detection of Helicobacter pylori infection in Chinese

BACKGROUND

Conventional (13)C-urea breath testing ((13)C-UBT) includes a test meal to delay gastric emptying, which, theoretically, improves the accuracy of the test. Citric acid has been proposed as the best test meal. However, recent studies have suggested that a test meal may not be necessary.

AIM

To investigate a new (13)C-UBT protocol without a test meal in a Chinese population.

METHODS

Consecutive dyspeptic patients referred for upper endoscopy were recruited. (13)C-UBT was performed on two separate days with or without a test meal (2.4 Gm citric acid) and compared with the 'gold standard' (CLO test and histology).

RESULTS

Two hundred and two patients were tested. Using receiver operating characteristics (ROC) analysis, the optimal delta-value and optimal measurement interval for UBT were 5% and 30 min, respectively, both with or without a test meal. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of (13)C-UBT with citric acid (96.5%, 97.7%, 98.2%, 95.6%, 97.0%) were similar to (13)C-UBT without a test meal (94.7%, 97.7%, 98.2%, 93.5%, 96.0%).

CONCLUSION

This simplified (13)C-UBT protocol without a test meal produced highly accurate and reliable results in the Chinese population.

The incidence of reflux oesophagitis after cure of Helicobacter pylori in a Japanese population

AIM

To investigate the incidence of reflux oesophagitis after antibacterial therapy for Helicobacter pylori infection in our patient population.

METHODS

Subjects were 451 H. pylori-infected patients (primary symptom: peptic ulcer disease in 347, nonulcer dyspepsia in 100, and reflux oesophagitis in four): 11 of these patients had reflux oesophagitis on study entry. H. pylori infection was treated by a proton pump inhibitor/amoxycillin-clarithromycin regimen for either 7 or 14 days. Each patient was examined by endoscopy before treatment and more than 6 months after treatment to compare oesophageal findings. In addition, 227 patients were interviewed regarding reflux symptoms, using symptom questionnaires, before and more than 6 months after treatment.

RESULTS

Among 440 patients who did not have reflux oesophagitis prior to antibacterial treatment (340 peptic ulcer patients and 100 nonulcer dyspepsia patients), 23 patients whose infection was eradicated developed reflux oesophagitis (5.4%). The 11 patients who had reflux oesophagitis prior to treatment were all successfully cured of infection. Six of these patients showed no change in their oesophagitis, while the condition improved in three and worsened in two. Symptom scores improved in 34 of the 36 patients who reported reflux symptoms. Among 19 patients who showed persistent infection, only one developed reflux oesophagitis (5.2%), while none complained of newly developed symptoms following treatment.

CONCLUSIONS

Development of reflux oesophagitis after treatment of H. pylori infection was observed in a Japanese population. However, the incidence of this condition was comparable between those with persistent H. pylori infection and those in whom the infection was eradicated.

Cure of Helicobacter pylori infection does not improve symptoms in non-ulcer dyspepsia patients-a double-blind placebo-controlled study

BACKGROUND

It remains controversial whether the cure of H. pylori infection improves NUD symptoms.

AIM

To conduct a double-blind placebo-controlled single centre study with concealed allocation to investigate this question.

PATIENTS AND METHODS

Ninety NUD patients with H. pylori infection were randomly assigned to either the treatment group (50 patients) or placebo group (40 patients). The treatment group received omeprazole, amoxycillin, clarithromycin and the placebo group received omeprazole and placebos for 7 days. Symptoms were assessed every week for up to 12 weeks after completion of medication by a symptom questionnaire. Alteration of histological parameters for gastritis was also evaluated.

RESULTS

The infection was cured in 41 out of 48 patients in the treatment group and none in the placebo group. There was no significant difference in the mean symptom scores at any assessment point up to 12 weeks between the treatment and placebo groups. Regarding histological parameters, activity and inflammation, not atrophy or intestinal metaplasia, were significantly improved in the treatment group.

CONCLUSION

Although histological parameters were significantly improved in the treatment group, there was no significant improvement in symptoms of NUD in the treatment group compared to placebo.

Insufficient diagnostic accuracy of imported serological kits for Helicobacter pylori infection in Japanese population

Although there are many reports of the high diagnostic accuracy of commercially available serologic kits for Helicobacter pylori infection in Western countries, they rarely has been investigated in oriental population. Accordingly we examined their usefulness in 492 Japanese patients with dyspeptic symptoms. Diagnostic accuracy of 4 imported serologic kits (HEL-p TEST, HM CAP, G.A.P IgG, Helico G2) was investigated using the (13)C-urea breath test as the gold standard. When intermediate results were excluded, the sensitivity, specificity and accuracy of these serologic tests ranged from 88.6% to 97.8%, 67.9% to 85.9%, and 87.9% to 91.4%, respectively, which were comparable with reported median accuracy in the Western population. However, there were many intermediate results in these tests, ranging from 5.3% to 23.0%. Their usefulness seemed to be limited in our patient population because of the large number of intermediate results.

Usefulness of a novel enzyme immunoassay for the detection of Helicobacter pylori in feces

BACKGROUND

In this study we assessed the reliability of a newly developed enzyme immunoassay (HpSA) kit for detecting Helicobacter pylori antigen in stool.

METHODS

This study included 309 patients, 147 of whom were defined as positive and 162 as negative by the 13C-urea breath test, rapid urease test, and pathologic findings. From these patients fresh stool specimens were collected for HpSA.

RESULTS

When 0.100 was adopted as the cut-off value, in accordance with the manufacturer's recommendations, the sensitivity, specificity, and accuracy of the HpSA were 98.0%, 87.0%, and 92.2%, respectively. However, these values were much improved when a cut-off value of 0.300 was adopted, which was obtained with our receiver-operator characteristics curve; with this value the sensitivity, specificity, and accuracy of HpSA were 93.9%, 95.7%, and 94.8%, respectively.

CONCLUSION

These results indicate that HpSA is a highly reliable diagnostic method for H. pylori infection and is useful in confirming eradication.

How useful is the detection kit for antibody to Helicobacter pylori in urine (URINELISA) in clinical practice?

OBJECTIVE

Increased knowledge of the significance of Helicobacter pylori (H. pylori) infection in gastric disorders has accelerated the trend of screening patients with dyspepsia for its infection. Serological examination of antibody for H. pylori has been widely performed. Recently, a urine-based enzyme-linked immunosorbent assay (URINELISA) kit for detection of antibody for H. pylori has been developed. Accordingly, we evaluated its diagnostic accuracy in clinical practice.

METHODS

Subjects of this study were 132 patients who presented at our university hospital because of dyspeptic symptoms (81 men, 51 women; age, 41.5+/-1.4 yr). 13C urea breath test, blood drawing for serological antibody for H. pylori infection by four different kits, and urine collection for the URINELISA test for detection of the antibody were performed. Diagnostic accuracy of the commercially available antibodies in serum and in urine were investigated using the results of the 13C urea breath test as the gold standard.

RESULTS

Sensitivity, specificity, and accuracy of URINELISA were 86.3% (95% confidence intervals [CI], 76-93%), 91.5% (95% CI, 81-97%), and 88.6% (95% CI, 82-93%), respectively, which were comparable to those of imported serological kits.

CONCLUSIONS

The URINELISA kit for detecting anti-H. pylori antibody in urine provides diagnostic accuracy comparable to that of imported kits for detecting antibodies in serum and is considered to be clinically useful for the diagnosis of H. pylori infection.

Impact of rabeprazole, a new proton pump inhibitor, in triple therapy for Helicobacter pylori infection-comparison with omeprazole and lansoprazole

BACKGROUND

A recent trend in curative therapy for Helicobacter pylori infection is the so-called triple therapy, which consists of a proton pump inhibitor (PPI) and two different antimicrobials. Various regimens employing this triple therapy have been reported. However, little is known about the effectiveness of rabeprazole, a recently developed proton pump inhibitor, when used in the triple therapy.

AIM

To validate its usefulness by comparing rabeprazole with omeprazole and lansoprazole, in combination with amoxycillin and clarithromycin.

PATIENTS AND METHODS

221 H. pylori-positive patients with peptic ulcer disease were randomized to receive one of three different proton pump inhibitor/amoxycillin-clarithromycin (PPI/AC) regimens for 7 days. (i) OAC regimen (n = 75): omeprazole 20 mg b.d., amoxycillin (AMOX) 500 mg t.d.s. and clarithromycin (CAM) 200 mg b.d.; (ii) LAC regimen (n = 74): lansoprazole 30 mg b.d. , AMOX 500 mg t.d.s. and CAM 200 mg b.d.; and (iii) RAC regimen (n = 72): rabeprazole 20 mg b.d., AMOX 500 mg t.d.s. and CAM 200 mg b.d. Cure of the infection was determined by the 13C urea breath test 1 month after completion of the treatment.

RESULTS

Intention-to-treat based cure rates for OAC, LAC and RAC regimens were 85% (95% CI, 75-92), 84% (95%, CI 73-91) and 88% (95% CI, 78-94), respectively, and per protocol based cure rates of these regimens were 88% (95% CI, 78-94), 91% (95%, CI 82-99) and 93% (95% CI, 84-98), respectively. Adverse effects in the entire study population, which included diarrhoea, glossitis or skin rash, were reported by 15% of the patients, and complete compliance was achieved in 95% of these patients.

CONCLUSION

1-week proton pump inhibitor/AC regimens for H. pylori infection were effective in the Japanese population. Rabeprazole can be considered as equivalent to omeprazole and lansoprazole in the PPI/AC triple therapy.

Efficacy of 1 week omeprazole or lansoprazole-amoxycillin-clarithromycin therapy for Helicobacter pylori infection in the Japanese population

BACKGROUND

The effectiveness of curative therapy for Helicobacter pylori may vary according to the geographic region and patient population, thus the efficacy of each treatment regimen should be determined according to the specific patient population. However, there is no literature available concerning the efficacy of 1 week omeprazole-amoxycillin-clarithromycin (OAC) regimens for the cure of H. pylori infection in Japan.

METHODS

Helicobacter pylori-positive patients (224) with peptic ulcer disease or non-ulcer dyspepsia were randomized to receive one of three different omeprazole or lansoprazole-amoxycillin-clarithromycin (PPI/AC) regimens for 7 days: (1) OAC 20 regimen (n = 76), omeprazole (OPZ) 20 mg daily, amoxycillin (AMOX) 500 mg t.d.s. and clarithromycin (CAM) 200 mg b.d.; (2) LAC 30 regimen (n = 73), Lansoprazole (LPZ) 30 mg daily, AMOX 500 mg t.d.s. and CAM 200 mg b.d.; and (3) OPZ 40 regimen (n = 75), OPZ 20 b.d., AMOX 500 mg t.d.s. and CAM 200 mg b.d. Cure of the infection was determined by the [13C]-urea breath test, 1 month after completion of the treatment.

RESULTS

Intention-to-treat based cure rates for OAC 20, LAC 30 and OAC 40 regimens were 75.0% (95% CI, 64-84%), 82.2% (95%, CI 72-90), and 80.0% (95% CI, 69-88), respectively and per-protocol based cure rates of these regimens were 79.2% (95% CI, 68-88%), 83.3% (95%, CI 73-91), and 83.1% (95% CI, 72-91%), respectively. Adverse effects, which included diarrhoea, glossitis or skin rash, were reported by 26.1% of the patients. However, these were mild and did not affect compliance.

CONCLUSION

One week PPI/AC regimens for H. pylori infection with smaller proton pump inhibitors and antimicrobial dosages compared to regimens used in Western countries were revealed to provide sufficient cure rate (more than 80% by ITT analysis) with mild adverse effects in the Japanese population.

[13C]-urea breath test for assessment of cure of Helicobacter pylori infection at 1 month after treatment

Although the [13C]-urea breath test has been reported to provide high specificity and sensitivity, its reliability in determination of cure, including when and how the assessment of cure is made, is not fully established. Here we evaluate the reliability of judgment of cure after 1 month of therapy using the [13C]-urea breath test, including the appropriate time to assess its cure. Our subjects were 199 H. pylori-infected patients (144 men and 55 women; 50.5+/-0.76 years) who underwent cure therapy, took the breath test at 1 month, and underwent both the breath test and invasive tests using endoscopy at 6 months after completion of therapy. Accuracy of the breath test in judgment of cure at 1 month was investigated by comparing the results at 1 month with those at 6 months when cut-off value of the breath test was set at 5 per thousand. Chronologic alterations of the delta13C value were also analyzed in cured patients who underwent the breath test at 1, 3, and 6 months. In 167 (94.9%) of 176 patients whose breath test values were less than 5 per thousand, cure was reconfirmed at 6 months. In 14 (60.9%) of 23 patients whose values were greater than 5 per thousand, cure was demonstrated at 6 months. The mean delta13C values of 33 cured patients who took the breath test at 1 month and repeated the breath test at 3 and 6 months for any reasons were 4.14+/-0.74 per thousand, 2.02+/-0.23 per thousand, and 1.72+/-0.19 per thousand, respectively, and the value at 3 months was significantly smaller than that at 1 month. The reliability of assessment of cure by only the breath test at 1 month was sufficiently high (94.9%) once the patients were judged to be cured. However, because the breath test at 1 month yielded a high false-positive rate and the breath test values at 3 and 6 months were similar, evaluation of cure of H. pylori infection by the [13C]-urea breath test should preferably be done at 3 months after treatment to minimize false-positive results, or the concept of a borderline group should be established for patients with positive but relatively high delta13C values (5-10 per thousand) who repeated the breath test 3 months after treatment.