Diagnostic accuracy of the E-plate serum antibody test kit in detecting Helicobacter pylori infection among Japanese children

Causal relationship between Helicobacter pylori infection and IgA nephropathy: a bidirectional two-sample mendelian randomization study

IgA nephropathy (IgAN) is one of the most common primary glomerulonephritis, and serum Helicobacter pylori (H. pylori) antibody levels are increased in patients with IgA N, but the role of H. pylori infection in the pathogenesis of IgAN is unclear. In this study, we investigated whether there is a causal relationship and reverse causality between IgAN and H. pylori infection by using a bidirectional two-sample Mendelian randomization (MR) analysis. This study was estimated using inverse variance weighted (IVW), MR-Egger and weighted median methods, with the IVW method having the strongest statistical efficacy. Seven common serum H. pylori antibodies were selected as exposure factors for positive MR analysis. The results showed that there was no evidence of a causal relationship between H. pylori infection and IgAN. Reverse MR analysis showed that there was also no evidence that the occurrence of IgAN leads to an increased risk of H. pylori infection.

The chimeric UreB, FliD and Omp18 proteins for a sensitive and specific diagnosis of Helicobacter pylori infections

Background and Objectives

Helicobacter pylori is known as the main cause of gastrointestinal diseases including gastritis, gastric ulcer and stomach cancer. Serodiagnosis of H. pylori infection is a noninvasive and rapid method but the efficiency of this method is highly dependent to the antigens used. This study evaluated the efficacy of recombinant UreB-Omp18 and FliD for serodiagnosis of H. pylori infection.

Materials and Methods

The genes encoding for fliD, ureB, and omp18 was amplified by PCR and cloned into pET-22b and pET-28a vectors. The constructs were expressed in E. coli BL21 and purified by affinity chromatography. The antigenic properties and diagnostic potential of the recombinant proteins were analysed by immunoblotting and ELISA, respectively.

Results

The recombinant UreB-Omp18 and FliD with molecular weights of 48 kDa and 25 kDa were observed on SDS-PAGE and purified by the Ni-NTA column. The ELISA results showed that the sensitivity and specificity of recombinant UreB-Omp18 protein in serodiagnosis of H. pylori infection were 89% and 83%, respectively. Also, the sensitivity and specificity of the recombinant FliD protein were calculated to be 91% and 76%, respectively.

Conclusion

The results indicated that the recombinant UreB-Omp18 and FliD could diagnose H. pylori infection with high sensitivity and specificity.

No potential causal link between HP infection and IBD: A 2way Mendelian randomization study

Recent epidemiological research suggests a possible negative correlation between Helicobacter pylori infection and inflammatory bowel disease (IBD). However, conflicting studies have provided unclear evidence regarding these causal relationships. Therefore, recommending specific prevention and treatment strategies for H. pylori infection and IBD is challenging. We used various antibodies (anti-H. pylori IgG, VacA, and GroEl) related to H. pylori infection as indicators. We acquired relevant genetic variants from public databases within the Genome-wide Association Studies (GWAS) dataset using IBDs tool variables from 2 different GWAS datasets. We thoroughly examined the data and screened for IVs that fulfilled these criteria. Subsequently, Bidirectional Mendelian randomization (MR) was conducted to predict the potential causality between the 2. To ensure the accuracy and robustness of our results, we conducted a series of sensitivity analyses. Based on our comprehensive MR analysis, no potential causal relationship was observed between H. pylori infection and IBD. Across various methodologies, including IVW, MR-Egger, and weighted median, our findings showed P values > .05. The only exception was observed in the reverse MR analysis using the MR-Egger method, which yielded a P value of < .05. However, because the IVW method is considered the most statistically significant method for MR, and its P value was > .05, we do not believe that a potential causal relationship exists between them. Our sensitivity analysis did not suggest significant horizontal pleiotropism. Although heterogeneity was detected in the analysis of IBD (IIBDGC source) versus H. pylori GroEL antibody levels (MR-Egger, Qp = 0.038; IVW, Qp = 0.043), the results remained reliable because we selected IVW as a random-effects model in our MR analysis method. Based on our MR research, no direct correlation was observed between H. pylori infection and IBD risk. This implies that eradicating H. pylori may not provide substantial benefits in preventing or treating regional IBD, and vice versa. Nevertheless, the use of H. pylori serological index substitution has limitations, and further research using histological diagnosis and additional MR studies is required to comprehensively assess the link between H. pylori infection and IBD.

Sugary drink consumption and the subsequent risk of gastric cancer: The Japan Public Health Center-based Prospective Study

BACKGROUND/OBJECTIVES

Evidence on the association between sugary drink consumption and gastric cancer (GC) risk is limited, especially in Asian populations. This study aimed to investigate the association between consumption of sugary drinks (sugar-sweetened beverages and 100% fruit juices) and GC risk in a Japanese population.

SUBJECTS/METHODS

This study included 74,455 Japanese individuals aged 45-74 years (35,102 males and 39,353 females) who participated in a population-based cohort study (Japan Public Health Center-based Prospective Study). Sugary drinks were assessed using a food frequency questionnaire. Cox proportional hazard regression was used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs) of GC incidence according to the quintile of sugary drink consumption.

RESULTS

We identified 2141 patients with GC cases during 16.7 years of follow-up. Sugary drink consumption was not associated with GC risk. The multivariate HR of total, cardia, and non-cardia GC in the highest vs. lowest quintile of sugary drinks consumption in males was 0.98 (95% CI: 0.82-1.17; p-trend 0.48), 0.48 (95% CI: 0.23-0.99; p-trend 0.03), and 1.03 (95% CI: 0.86-1.24; p-trend 0.88), respectively. In females, the respective multivariate HRs were 1.03 (95% CI: 0.79-1.33; p-trend 0.47), 1.28 (95% CI: 0.32-5.12; p-trend 0.53), and 1.01 (95% CI: 0.78-1.32; p-trend 0.56). The results did not change significantly after adjusting for Helicobacter pylori infection and atrophic gastritis status in the subgroup analysis.

CONCLUSIONS

In this Japanese prospective cohort study, sugary drink consumption was not associated with GC risk.

Long-term Response of Helicobacter pylori Antibody Titer After Eradication Treatment in Middle-aged Japanese: JPHC-NEXT Study

BACKGROUND

Helicobacter pylori (H. pylori) is an established causative factor of gastric cancer. Although the expansion of insurance coverage has led to an increase in the number of patients treated for H. pylori, the population impact of eradication treatment for H. pylori has been scarcely investigated. This study aimed to clarify the long-term responses of H. pylori antibody titer after eradication treatment using large scale cross-sectional data from the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT Study).

METHODS

A total of 55,282 Japanese participants aged 40 to 74 years residing in 16 areas provided blood samples from 2011 through 2016. From these, treated (n = 6,276) and untreated subjects who were seropositive for H. pylori or had serological atrophy (n = 22,420) formed the study population (n = 28,696). Seropositivity was defined as an anti-H. pylori IgG titer of ≥10 U/mL. Antibody level was compared among subjects according to self-reported treatment history as untreated, and treated for less than 1 year (<1Y), 1 through 5 years (1-5Y), and 6 or more years ago (6Y+).

RESULTS

Median serum antibody titer was 34.0 U/mL, 7.9 U/mL, 4.0 U/mL, and 2.9 U/mL for the untreated, <1Y, 1-5Y, and 6Y+ groups, respectively. While those treated for H. pylori within the previous year had a 76.8% lower antibody titer compared to untreated subjects, approximately 41% of subjects were still seropositive.

CONCLUSION

A significant reduction in H. pylori antibody titer occurs within 1 year after eradication treatment, but that a long period is needed to achieve complete negative conversion.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

Association of B Vitamins and Methionine Intake with the Risk of Gastric Cancer: The Japan Public Health Center-based Prospective Study

Dietary intake of B vitamins and methionine might associate with carcinogenesis due to their role in DNA synthesis and methylation. Owing to the previous inconsistent findings on gastric cancer risk, we aimed to examine the associations between dietary intakes of B vitamins and methionine and the risk of gastric cancer, according to sodium intake.We included 86,820 Japanese individuals who completed a validated food frequency questionnaire with 138 food items in the Japan Public Health Center-based Prospective Study. Cox proportional hazards regression was used to obtain HRs and 95% confidence intervals (CI) of gastric cancer according to separate intakes of folate, vitamin B6, vitamin B12, and methionine after adjusting for confounding factors, including Helicobacter pylori and atrophic gastritis in the subgroup analysis.We identified 2,269 gastric cancer cases within a median of 15.4 years of follow-up. We found no association between any of the dietary intakes of folate, vitamin B6, vitamin B12, or methionine with the risk of gastric cancer. In the stratified analysis by sodium intake, we observed a positive association between folate intake and risk of gastric cancer among participants with a high sodium intake (≥4.5 g/day) [HR = 1.28 (95% CI, 1.06-1.56), P _trend = 0.001; P _interaction = 0.02]. Meanwhile, there was no association between folate intake and risk of gastric cancer among participants with low sodium intake (<4.5 g/day) [HR = 0.94 (95% CI, 0.73-1.21), P _trend = 0.49].In conclusion, we found no association between any dietary intakes of folate, vitamin B6, vitamin B12, and methionine with the risk of gastric cancer. PREVENTION RELEVANCE: The increased intake of B vitamins and methionine in populations with adequate dietary intake of these nutrients showed no association with the risk of gastric cancer.

The updated JSPGHAN guidelines for the management of Helicobacter pylori infection in childhood

The Japan Pediatric Helicobacter pylori Study Group published the first guidelines on childhood H. pylori infection in 1997. They were later revised by the Japanese Society for Pediatric Gastroenterology, Hepatology and Nutrition (JSPGHAN). The H. pylori eradication rates, when employing triple therapy with amoxicillin and clarithromycin, currently recommended as the first-line therapy of H. pylori infection in Japan, have substantially decreased, creating an important clinical problem worldwide. In Japanese adults, the "test-and-treat" strategy for H. pylori infection is under consideration as an approach for gastric cancer prevention. However, the combined North American and European pediatric guidelines have rejected such a strategy for asymptomatic children. As risk for gastric cancer development is high in Japan, determining whether the "test-and-treat" strategy can be recommended in children has become an urgent matter. Accordingly, the JSPGHAN has produced a second revision of the H. pylori guidelines, which includes discussion about the issues mentioned above. They consist of 19 clinical questions and 34 statements. An H. pylori culture from gastric biopsies is recommended, not only as a diagnostic test for active infection but for antimicrobial susceptibility testing to optimize eradication therapy. Based upon antimicrobial susceptibility testing of H. pylori strains (especially involving clarithromycin), an eradication regimen including use of the antibiotics to which H. pylori is susceptible is recommended as the first-line therapy against H. pylori-associated diseases. The guidelines recommend against a "test-and-treat" strategy for H. pylori infection for asymptomatic children to protect against the development of gastric cancer because there has been no evidence supporting this strategy.

Inverse time trends of peptic ulcer and reflux esophagitis show significant association with reduced prevalence of Helicobacter pylori infection

INTRODUCTION

Recent prevalence and trends of gastric/duodenal ulcer (GU/DU) and reflux esophagitis (RE) are inadequate.

METHODS

We reviewed the records of consecutive 211,347 general population subjects from 1991 to 2015.

RESULTS

During the 25 years, the prevalence of GU and DU has gradually decreased (from 3.0% to 0.3% and from 2.0% to 0.3%) whereas that of RE has markedly increased (from 2.0% to 22%). The prevalence of Helicobacter pylori (HP) infection has decreased from 49.8% (in 1996) to 31.2% (in 2010). Multivariable logistic regression analyses demonstrated that HP infection was positively associated with GU/DU and negatively associated with RE with statistical significance. The panel data analyses showed that reduced rate of HP infection is proportionally correlated with decrease of GU/DU and inversely correlated with increase of RE. It is further suggested other latent factors should be important for changed prevalence of these three acid-related diseases. Age-period-cohort analysis indicated the significant association of older age, male gender, and absence of HP infection with RE.

CONCLUSIONS

The prevalence of GU and DU has gradually decreased whereas that of RE has markedly increased in Japan. Inverse time trends of peptic ulcer and reflux esophagitis are significantly associated with reduced prevalence of HP infection. KEY MESSAGES The prevalence of gastric and duodenal ulcer has gradually decreased whereas that of reflux esophagitis has markedly increased in Japan. The prevalence of Helicobacter pylori infection in Japan has greatly decreased from 49.8% to 31.2% during the 14 years (from 1996 to 2010). Inverse time trends of peptic ulcer and reflux esophagitis are associated with reduced prevalence of Helicobacter pylori infection with statistical significance.

Usefulness and Limitations of a Serum Screening System to Predict the Risk of Gastric Cancer

Objective The aim of the present study was to evaluate the effectiveness and limitations of a serum screening system for predicting the risk of gastric cancer. Methods Serum pepsinogen I (PG I)/pepsinogen II (PG II) and Helicobacter pylori (HP) antibody levels were measured. Subjects were classified into four groupsaccording to their serological status (the ABC classification system). The grade of atrophic gastritis was assessed endoscopically. We evaluated gastric cancer detection rates according to the ABC classification system and the endoscopic grade of atrophy. Patients Individuals who underwent esophagogastroduodenoscopy (EGD) in a health check were prospectively enrolled in the present study. Results According to the ABC classification system, the gastric cancer detection rates in groups A, B, C, and D were 0.07% (4/6,105), 0.5% (8/1,739), 0.8% (16/2,010), and 1.1% (3/281), respectively. The gastric cancer detection rates in subjects with no atrophy, closed type (C-type) atrophy, and open type (O-type) atrophy were 0% (0/4,567), 0.2% (4/2,581), and 0.9% (27/2,987), respectively. In group A (HP(-)/PG(-)), the proportions of subjects with no atrophy, C-type atrophy, and O-type atrophy were 71.2%, 22.8%, and 6.0%, respectively. In group A, the gastric cancer detection rates in subjects with no atrophy, C-type atrophy, and O-type atrophy were 0%, 0.07%, and 0.8%, respectively. Conclusion The ABC classification system is useful for predicting the risk of gastric cancer. However, this system was limited in group A, which included individuals with a high risk of developing gastric cancer. An endoscopic diagnosis of atrophy may be more effective than the ABC classification system for predicting the risk of gastric cancer.

Application of 16S rRNA gene sequencing in Helicobacter pylori detection

Helicobacter pylori is one of the major stomach microbiome components, promoting development of inflammation and gastric cancer in humans. H. pylori has a unique ability to transform into a coccoidal form which is difficult to detect by many diagnostic methods, such as urease activity detection, and even histopathological examination. Here we present a comparison of three methods for H. pylori identification: histological assessment (with eosin, hematoxylin, and Giemsa staining), polymerase chain reaction (PCR) detection of urease (ureA specific primers), and detection by 16S rRNA gene sequencing. The study employed biopsies from the antral part of the stomach (N = 40). All samples were assessed histologically which revealed H. pylori in eight patients. Bacterial DNA isolated from the bioptates was used as a template for PCR reaction and 16S rRNA gene sequencing that revealed H. pylori in 13 and in 20 patients, respectively. Thus, 16S rRNA gene sequencing was the most sensitive method for detection of H. pylori in stomach biopsy samples.

Association between Helicobacter pylori infection, eradication and diabetes mellitus

AIMS/INTRODUCTION

It is suspected that Helicobacter pylori is associated with extradigestive diseases including diabetes. So far, a number of studies have examined the association between H. pylori and diabetes, and the results were conflicting. The aim of the present study was to examine the association between H. pylori infection, eradication and diabetes.

MATERIALS AND METHODS

The present cross-sectional study was carried out using data from annual health checkups carried out at the Toranomon Hospital Health Management Center. The status of H. pylori infection, determined by serum antibodies and history of eradication, was categorized into three groups as "never," "current" and "past." The association between H. pylori infection and diabetes was examined using logistic regression.

RESULTS

Of 21,634 participants, 6,530 (30.2%) had a current or past history of H. pylori infection, and 1,184 (5.5%) were identified as having diabetes. Multivariate adjusted odds ratios for diabetes compared with the "never" group were 1.36 (95% confidence interval 1.10-1.67) for the "current" group and 0.92 (95% confidence interval 0.79-1.07) for the "past" group. The association between H. pylori infection and diabetes was also observed among participants without a history of eradication.

CONCLUSIONS

We found that current H. pylori infection was associated with an increased risk of diabetes, and the increased risk was not observed among participants after eradication. The results were concordant with the hypothesis that H. pylori infection increases the risk of diabetes. Further studies are necessary to validate the present results.

Clinical features of Helicobacter pylori antibody-positive junior high school students in Nagano Prefecture, Japan

BACKGROUND

Previously, we conducted an epidemiological study screening for Helicobacter pylori antibody positivity among Japanese junior high school students. In this study, we updated the epidemiological data and assessed the clinical features of H pylori antibody-positive junior high school students.

MATERIALS AND METHODS

We assessed H pylori antibody-positive subjects who were identified between 2012 and 2015 at four junior high schools in Nagano Prefecture, Japan. H pylori infection was confirmed by urea breath test (UBT) or endoscopic examination. Endoscopy was performed after obtaining consent from the subject and their guardians. Eradication therapy consisted of triple therapy with proton pump inhibitor (PPI), amoxicillin (AMPC), and clarithromycin (CAM) or metronidazole (MNZ) for seven days. Eradication of H pylori was confirmed by UBT. We reviewed subjects' characteristics, endoscopic findings, histological findings, eradication regimes, outcomes, and adverse effects.

RESULTS

The overall prevalence of H pylori antibody positivity was 3.2% (42/1298). We assessed thirteen H pylori antibody-positive subjects. Eight subjects had a family history of H pylori infection. Six subjects had abdominal pain, and two subjects had iron deficiency anemia (IDA). Twelve subjects underwent endoscopy; one subject had duodenal ulcer, eleven subjects had antral nodular gastritis, and six subjects showed grade 2 closed type atrophic border according to the Kimura-Takemoto classification. All subjects received eradication therapy; CAM was used in five subjects with CAM susceptibility as well as in three subjects with unknown information on CAM susceptibility, and MNZ was used in five subjects with CAM resistance. Eradication was successful in twelve subjects (one unconfirmed). There were three mild adverse effects (abdominal pain or diarrhea).

CONCLUSIONS

Helicobacter pylori test for junior high school students represents an opportunity to diagnose the peptic ulcer, iron deficiency anemia, and gastric atrophy.

Serum Pepsinogen Values in Japanese Junior High School Students With Reference to Helicobacter Pylori Infection

Background

Distributions of serum pepsinogen (PG) values were assessed in Helicobacter pylori-infected and non-infected junior high school students (aged 12–15 years) in Japan.

Methods

All junior high school students (1,225 in total) in Sasayama city, who were basically healthy, were asked to provide urine and serum samples, which were used to measure urine and serum H. pylori antibodies using ELISA kits and PG values. The subjects, whose urine and serum antibodies were both positive, were considered H. pylori infected.

Results

Of the 187 subjects who provided urine and blood samples, 8 were infected, 4 had discrepant results, 4 had negative serum antibody titers no less than 3.0 U/ml, and 171 were non-infected. In the H. pylori non-infected subjects, the median PG I and PG II values and PG I to PG II ratio (PG I/II) were 40.8 ng/mL, 9.5 ng/mL, and 4.4, respectively, whereas in the infected subjects, these values were 55.4 ng/mL, 17.0 ng/mL, and 3.3, respectively (each P < 0.01). In the non-infected subjects, PG I and PG II were significantly higher in males than in females (P < 0.01).

Conclusions

The PG I and PG II values were higher, and the PG I/II was lower in H. pylori infected students than in non-infected students. In H. pylori non-infected students, males showed higher PG I and PG II values than females. The distributions of PG values in junior high school students differed from those in adults.

Diagnostic Accuracy of Latex Agglutination Turbidimetric Immunoassay in Screening Adolescents for Helicobacter pylori Infection in Japan

BACKGROUND/AIMS

Serologic tests are commonly used for screening Helicobacter pylori infection because they not only provide quick results but also are inexpensive. A new latex agglutination serum antibody assay (LZ test) has been developed and it is expected to be as effective as conventional assays. This study aimed to calculate a reliable cutoff value for the LZ test and to estimate the sensitivity and specificity of the cutoff value in screening adolescents for H. pylori infection in Japan.

METHODS

We screened junior high school students in Akita Prefecture, Japan, for H. pylori infection. We used the data of 213 such students who underwent H. pylori stool antigen (HpSA) tests in 2016. The students who had positive results with HpSA tests were diagnosed with H. pylori infection. Of the 213 students, 209 underwent the LZ test.

RESULTS

The prevalence rate of H. pylori infection was 3.8% (8/209). The area under the curve for the LZ test was 0.88. The cutoff value of the LZ test was determined to be 3.1 U/mL. At this value, the sensitivity and specificity were 87.5 and 91.5%, respectively.

CONCLUSION

The accuracy of the LZ test in adolescents was well balanced for sensitivity and specificity as well as for tolerable results.

Hypergastrinemia in Long-Term Use of Proton Pump Inhibitors

BACKGROUND/AIM

The use of proton pump inhibitors (PPIs) is known to lead to hypergastrinemia; however, the data in patients with atrophic gastritis is still lacking. The aim of this study was to investigate the effects of long-term PPIs use on the gastrin levels in patients with atrophic gastritis and to determine factors affecting hypergastrinemia in long-term users of PPIs.

METHODS

Serum Helicobacter pylori IgG, gastrin and pepsinogen levels were measured. Atrophic gastritis was assessed by upper gastrointestinal endoscopies based on the Kimura-Takemoto classification and pepsinogen levels. CYP2C19 polymorphisms were assessed using DNA extracted from peripheral blood.

RESULTS

A total number of 382 patients (275 men and 107 women) were enrolled. Median serum gastrin levels were higher in PPI users than in non- users (234 vs. 113 pg/mL, p < 0.001) and in women than in men (252 vs. 155 pg/mL, p = 0.006). Gastrin levels were significantly associated with corpus atrophy only in the subgroup of non-users of PPIs. Multivariate analysis revealed that hypergastrinemia (over 150 pg/mL) was significantly associated with PPI use (OR 5.30; 95% CI 3.32-8.47), women (OR 2.22; 95% CI 1.33-3.72) and corpus atrophy (OR 1.82; 95% CI 1.14-2.90).

CONCLUSION

PPI use, women and corpus atrophy were risk factors for hypergastrinemia. Gender, but not corpus atrophy, affected the gastrin levels in long-term users of PPIs.

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.

Cutoff Pepsinogen Level for Predicting Unintendedly Eradicated Cases of Helicobacter pylori Infection in Subjects with Seemingly Normal Pepsinogen Levels

BACKGROUNDS/AIMS

In the ABC method, which is a method for risk stratification of gastric cancer using serum anti-Helicobacter pylori antibody and pepsinogen (PG) test, subjects with normal PG and seronegative for H. pylori are named as "Group A" and are regarded as having a low risk of gastric cancer. These "Group A" subjects include unintentionally eradicated cases at relatively high risk, and this study aimed to identify these subjects.

METHODS

Of the 109 subjects, 76 were classified as uninfected Group A subjects with negative histologic H. pylori infection and no histologic and endoscopic atrophy, and 33 subjects were classified serologically as Group A after successful eradication, which are serologically equal to the unintendedly eradicated cases in Group A. The usefulness of measuring PG levels to detect post-eradication cases was validated by using a receiver operating characteristic (ROC) curve analysis.

RESULTS

The area under the ROC curve for PGI level was 0.736 ± 0.06 (p < 0.01; cutoff value, 37.0 ng/mL; sensitivity, 77.6%; specificity, 72.7%), and that for the PGI/II ratio was 0.660 ± 0.06 (p < 0.01; cutoff value, 5.1; sensitivity, 84.2%; specificity, 43.4%).

CONCLUSION

PGI levels of ≤37 ng/mL and PGI/II ratios of ≤5.1 effectively identified unintendedly eradicated cases in Group A.

Changing trends in the prevalence of H. pylori infection in Japan (1908-2003): a systematic review and meta-regression analysis of 170,752 individuals

Changing trends in the prevalence of H. pylori infection in the general population over time are thought to be the main driving force behind the declining gastric cancer mortality in Japan. However, whether the prevalence of H. pylori infection itself shows a birth-cohort pattern needs to be corroborated. We performed a systematic review of studies that reported the prevalence of H. pylori infection among Japanese individuals. Meta-regression was conducted in the framework of a generalized additive mixed model (GAMM) to account for heterogeneity in the prevalence of H. pylori infection as a function of birth year. The prevalence of H. pylori infection confirmed a clear birth cohort pattern: the predicted prevalence (%, 95% CI) was 60.9 (56.3–65.4), 65.9 (63.9–67.9), 67.4 (66.0–68.7), 64.1 (63.1–65.1), 59.1 (58.2–60.0), 49.1 (49.0–49.2), 34.9 (34.0–35.8), 24.6 (23.5–25.8), 15.6 (14.0–17.3), and 6.6 (4.8–8.9) among those who were born in the year 1910, 1920, 1930, 1940, 1950, 1960, 1970, 1980, 1990, and 2000, respectively. The present study demonstrated a clear birth-cohort pattern of H. pylori infection in the Japanese population. The decreased prevalence of H. pylori infection in successive generations should be weighed in future gastric cancer control programs.

Overexpression of leucine-rich α2-glycoprotein-1 is a prognostic marker and enhances tumor migration in gastric cancer

Gastric cancer is one of the most common malignant tumors. Although improvement in chemotherapy has been achieved, the clinical prognosis of advanced gastric cancer remains poor. Therefore, it is increasingly important to predict the prognosis and determine whether patients should or should not receive neoadjuvant or adjuvant chemotherapy. Leucine‐rich α2‐glycoprotein‐1 (LRG1) is overexpressed during inflammation and is associated with various malignancies. In this study, we assessed LRG1 expression in cancer specimens and in the sera of patients with cancer to clarify the usefulness of LRG1 as a biomarker in gastric cancer. This study enrolled 239 (for immunohistochemical staining; IHC) and 184 (for ELISA) patients with gastric cancer. Results of IHC showed that LRG1 expression was significantly associated with histological type, lymphatic and venous invasion, tumor and node factors, and disease stage. Overall survival was significantly worse in the high LRG1 expression group than in the low LRG1 group (P = 0.0003). Cox multivariate analysis of overall survival revealed that LRG1 expression was an independent prognostic factor (P = 0.0258). Serum LRG1 was significantly higher in gastric cancer patients than in healthy volunteers, and increased as the pathological stage progressed. Furthermore, a significant correlation was revealed between serum LRG1 level and LRG1 expression with IHC (P < 0.0001). Inhibition of LRG1 significantly decreased cell proliferation in vitro (migratory and invasive capacity of gastric cancer cells). These results suggest that LRG1 expression in tumors and serum may be a useful prognostic marker in gastric cancer patients.

Higher dietary cholesterol and ω-3 fatty acid intakes are associated with a lower success rate of Helicobacter pylori eradication therapy in Japan

Background:Helicobacter pylori infection is a known risk factor for duodenal ulcers, gastritis, and gastric cancer. The eradication of H. pylori is successful in treating these disorders; however, the success rate of eradication therapy is declining. There may be an interaction with nutrient intake to account for this decline.Objective: We investigated the influence of food and nutrient intake on H. pylori eradication therapy.Design: In this study, 4014 subjects underwent endoscopy, were tested for serum antibodies to H. pylori (2046 positive; 51.0%), and had their food intake assessed with the use of a food-frequency questionnaire (FFQ). Of the positive subjects, endoscopies showed that 389 (19.0%) had gastritis and/or duodenal ulcers and were also positive for a ¹³C-urea breath test (UBT). These 389 subjects received 1-wk H. pylori eradication therapy with lansoprazole, amoxicillin, and clarithromycin and a second UBT 8 wk after treatment. Complete demographic characteristics, serum lipid, insulin, glycated hemoglobin, C-reactive protein (CRP), and creatinine concentrations as well as complete FFQs were available for 352 subjects. Multivariate logistic regression analyses were performed to determine factors that were associated with successful H. pylori eradication therapy.Results: The success rate of eradication therapy was 60.4% (235 of 389). Factors associated with the failure of eradication therapy included increased age (P = 0.02), higher CRP concentrations (P < 0.01), higher dietary cholesterol (P < 0.01) or egg intake (P < 0.01), higher ω-3 (n-3) fatty acid (P = 0.02) or fish intake (P = 0.01), and higher vitamin D intake (P = 0.02). Moreover, the higher vitamin D intake was strongly linked to higher fish intake. A limitation of the study is that we did not assess the antibiotic resistance of H. pyloriConclusions: Our results indicate that higher egg and fish intake may be negatively correlated with successful H. pylori eradication therapy in H. pylori-positive subjects with gastritis and/or duodenal ulcers.

Rapid urine antibody test for Helicobacter pylori infection in adolescents

BACKGROUND

Helicobacter pylori infection is associated with gastric cancer; thus, early diagnosis and treatment are crucial. Given that H. pylori infection in adolescents or young adults has few symptoms, screening tests are necessary for this population. In this study, the accuracy of the rapid urine H. pylori antibody (u-HpAb) test was evaluated and compared with that of urine and serum H. pylori enzyme-linked immunosorbent assay (u-HpELISA and s-HpELISA, respectively) in junior high school students.

METHODS

All 1,225 students attending the junior high schools in Sasayama City were invited to participate in this study. Urine and blood samples were assayed for anti-H. pylori immunoglobulin G antibodies, and rapid u-HpAb was performed by three investigators independently. When all investigators were in agreement, the test was confirmed as positive or negative. Non-concordance was defined as undetermined.

RESULTS

In total, 187 students participated in this study and provided both urine and blood samples. Three students had undetermined rapid u-HpAb. Excluding these results, the positivity rate of rapid u-HpAb was 3.3% (6/184), whereas that for u-HpELISA and s-HpELISA was 4.8% (10/187) and 5.9% (11/187), respectively. Using s-HpELISA and u-HpELISA as the standards, the sensitivity, specificity, positive predictive value, and negative predictive value of rapid u-HpAb were 85.7%, 100%, 100%, and 99.4%, respectively, excluding the undetermined rapid u-HpAb results.

CONCLUSIONS

Rapid urine-HpAb test had excellent specificity but relatively low sensitivity.

Helicobacter pylori infection and its related factors in junior high school students in Nagano Prefecture, Japan

BACKGROUND

There have been few reports on Helicobacter pylori (H. pylori) infection in asymptomatic Japanese children and adolescents. We hypothesized that the prevalence of H. pylori infection is very low among Japanese children and that clinical variables such as serum pepsinogen and iron levels are associated with H. pylori infection.

MATERIALS AND METHODS

We conducted a cross-sectional analysis of a sample of 454 junior high school students aged 12-15 years in four areas in Nagano Prefecture. A commercial ELISA kit (E-plate Eiken H. pylori antibody) was used to measure IgG antibody against H. pylori. Serum pepsinogen and iron levels were also measured using standard methods. A urea breath test was performed for seropositive students.

RESULTS

The overall prevalence of H. pylori was 3.1% (14/454). There were no significant differences in H. pylori prevalence among mountain, rural, and urban areas. The mean level of both serum pepsinogen (PG I) and PG II was significantly increased in the seropositive subjects compared with the seronegative subjects. When the cutoff values for adults (PG I: 70 ng/mL and PG I/II ratio: 3) were used, 4 of 14 subjects had PG I ≤70 ng/mL and PG I/II ratio ≤3. The results of a logistic regression analysis showed that low serum iron levels were significantly associated with H. pylori infection (P=.02).

CONCLUSIONS

The prevalence of H. pylori infection is as low as 3% among junior high school students aged 12-15 years in Japan. The disappearance of H. pylori is accelerating in Japanese children.

Diagnosis of Helicobacter pylori infection: Current options and developments

Accurate diagnosis of Helicobacter pylori (H. pylori) infection is a crucial part in the effective management of many gastroduodenal diseases. Several invasive and non-invasive diagnostic tests are available for the detection of H. pylori and each test has its usefulness and limitations in different clinical situations. Although none can be considered as a single gold standard in clinical practice, several techniques have been developed to give the more reliable results. Invasive tests are performed via endoscopic biopsy specimens and these tests include histology, culture, rapid urease test as well as molecular methods. Developments of endoscopic equipment also contribute to the real-time diagnosis of H. pylori during endoscopy. Urea breathing test and stool antigen test are most widely used non-invasive tests, whereas serology is useful in screening and epidemiological studies. Molecular methods have been used in variable specimens other than gastric mucosa. More than detection of H. pylori infection, several tests are introduced into the evaluation of virulence factors and antibiotic sensitivity of H. pylori, as well as screening precancerous lesions and gastric cancer. The aim of this article is to review the current options and novel developments of diagnostic tests and their applications in different clinical conditions or for specific purposes.

Analysis of negative result in serum anti-H. pylori IgG antibody test in cases with gastric mucosal atrophy

The purpose is to elucidate factors related to negative results of anti-H. pylori antibody test in cases with gastric mucosal atrophy. A total of 859 individuals without past history of eradication therapy for H. pylori (545 males, 314 females; mean age 52.4 years) who underwent an upper GI endoscopy examination and serological test were enrolled as subjects. Serological testing was performed using SphereLight H. pylori antibody J^®, and endoscopic findings of gastric mucosal atrophy by the classification of Kimura and Takemoto and post-eradication findings were analyzed. The positive rates for the anti-H. pylori antibody test in subjects with and without gastric mucosal atrophy were 85.6% and 0.9%, respectively. In analysis of subjects with gastric mucosal atrophy, a low positive rate and serum titer was observed in subjects with C1, C2 and O3 atrophy. When the analysis was performed separately in male and female subjects, low positive rate was observed in males with O3 atrophy and females with C2 atrophy. Suspected post-eradication endoscopic findings were more frequently observed in cases with C2 atrophy. In conclusion, negative result of anti-H. pylori antibody test was frequently observed in middle-aged subjects with C1, C2 and O3 gastric mucosal atrophy.

Epidemiology and Diagnosis of Helicobacter pylori infection

During the period reviewed, prevalence studies were essentially performed in less economically advanced countries and a high prevalence was found. The traditional risk factors for Helicobacter pylori positivity were mostly found. Transmission studied by molecular typing showed a familial transmission. The eventual role of water transmission was explored in several studies with controversial results. Concerning diagnosis, most of the invasive and noninvasive methods used for the diagnosis of H. pylori infection are long standing with efficient performance. The most interesting recent improvements in H. pylori diagnosis include advances in endoscopy, developments in molecular methods, and the introduction of omics-based techniques. Interpretation of old or newer method should take into account the pretest probability and the prevalence of H. pylori in the population under investigation.

Comparison of Serum IgG Antibody Test with Gastric Biopsy for the Detection of Helicobacter Pylori Infection among Egyptian Children

BACKGROUND:

In developing countries, Helicobacter pylori (H. pylori) infection is mainly acquired during childhood and may be a predisposing factor for peptic ulcer or gastric cancer later in life. Noninvasive diagnostic tools are particularly useful in children for screening tests and epidemiological studies. Data on serologic testing of children are lacking. Accurate noninvasive tests for diagnosing Helicobacter pylori infection in children are strongly required.

AIM:

The aim of this study was to evaluate the performance of a serological test (serum IgG antibody for H. pylori) in Egyptian children with recurrent abdominal pain necessitating endoscopy.

SUBJECTS AND METHODS:

One hundred children, referred to the endoscopy unit at Mansoura University. Upper endoscopy was done for each with rapid urease test (RUT) and histological examination as the gold standard test for detection of H. pylori infection. Serum samples were collected for detecting IgG for H. pylori infection.

RESULTS:

The mean age of the subjects included in the study was 7.23 ± 1.94 year. Serological test (IgG to H. pylori) was positive in 60% of all cases. A highly significant association between the standard test and the serological test at a cutoff > 10 U/ml at p = 0.001 were detected for the diagnosis of H. pylori infection. The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio for the IgG antibody a cutoff > 10 U/ml, were 96.5%, 93%, 13.83, 0.038 respectively.

CONCLUSION:

Serum IgG antibody to H. pylori infection has a high diagnostic value and can be considered as a suitable and reliable noninvasive test for detection of H. pylori infection.

New Diagnostic Strategies for Detection of Helicobacter pylori Infection in Pediatric Patients

Helicobacter pylori (H pylori) is a common chronic bacterial infection that is an important cause of peptic ulcer disease and gastroduodenal disease in children. H pylori is also associated with extragastric manifestations, including growth reduction, iron-deficiency anemia, and idiopathic thrombocytopenic purpura. Current guidelines recommend endoscopy with biopsy for the definitive demonstration of H pylori infection. In contrast to serology, the fecal antigen test and the urea breath test provide reliable, sensitive, and specific results for detecting active H pylori infection in children before and after treatment. The first-line treatment option for pediatric patients is triple therapy with a proton pump inhibitor and 2 antibiotics, which include amoxicillin and clarithromycin or metronidazole. Decreasing eradication rates and the emergence of antibiotic-resistant strains of H pylori have led to the use of other treatments, such as sequential therapy or triple therapy with newer antibiotics, particularly in geographic areas with high rates of antibiotic resistance. Patients should be tested after treatment to confirm eradication, as the absence of symptoms does not necessarily mean that H pylori is no longer present. This clinical roundtable monograph provides an overview of H pylori infection, as well as expert insight into the diagnosis and management of H pylori infection in children.