Noninvasive evaluation of Helicobacter pylori therapy: role of fasting or postprandial gastrin, pepsinogen I, pepsinogen II, or serum IgG antibodies

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.

Pepsinogen testing for evaluation of the success of Helicobacter pylori eradication at 4 weeks after completion of therapy

BACKGROUND AND OBJECTIVE

Pepsinogen levels in plasma are increased by inflammation in the gastric mucosa, including inflammation resulting from Helicobacter pylori infection. A decrease in pepsinogen II level has been suggested as a reliable marker to confirm the successful eradication of infection. The aim of our study was to evaluate the potential role of pepsinogens I and II, gastrin-17 and H. pylori antibodies in confirming successful eradication.

MATERIAL AND METHODS

Altogether 42 patients (25 women, 17 men), mean age 45 years (range 23-74), were enrolled. Pepsinogens I and II, gastrin-17 and H. pylori IgG antibodies were measured in plasma samples using an ELISA test (Biohit, Oyj., Finland) before the eradication and 4 weeks after completing the treatment. The success of eradication was determined by a urea breath test.

RESULTS

Eradication was successful in 31 patients (74%) and unsuccessful in 11 patients (26%). Pepsinogen II decreased significantly in both the successful (P=0.029) and unsuccessful (P=0.042) eradication groups. Pepsinogen I decreased significantly in the successful (P=0.025) but not the unsuccessful (P=0.29) eradication group. The pepsinogen I/II ratio increased in the successful eradication group (P=0.0018) but not in the group in which treatment failed (P=0.12). There were no differences in gastrin-17 or H. pylori antibody values.

CONCLUSIONS

A decrease in pepsinogen II levels cannot be used as a reliable marker for the successful eradication of H. pylori 4 weeks after the completion of treatment. The increase in pepsinogen I/II ratio reflects differences in pepsinogen production following the eradication irrespective of improvement in atrophy.

Quantification of serum levels of pepsinogens and gastrin to assess eradication of Helicobacter pylori

BACKGROUND & AIMS

We investigated whether serum levels of pepsinogen (sPG)I and sPGII, the ratio of sPGI to sPGII, or serum levels of gastrin-17 (sG17), can be used to assess eradication of Helicobacter Pylori 8 weeks after treatment.

METHODS

We performed a prospective study of 228 consecutive patients with H pylori infections. At the start of the trial (baseline), patients were assessed using the (13)C-urea breath test ((13)C-UBT) and endoscopy, and serum levels of pepsinogens and gastrin levels were measured. Patients were offered a 7-day triple therapy and asked to return 8 weeks after treatment for another (13)C-UBT and measurements of serum levels of sG17, sPGI, and sPGII (175 patients completed the study).

RESULTS

The eradication rate of H pylori was 67%. Percentage variation in levels of sPGI and sPGII, the ratio of sPGI to sPGII, and in levels of sG17 resulted in area under the curve values of 0.858, 0.973, 0.940, and 0.810, respectively, for H pylori eradication. A decrease of 22.7% or greater in the level of sPGII detected H pylori eradication with 100% sensitivity and 96.6% specificity. Spectrum analysis did not identify differences in accuracy.

CONCLUSIONS

Percentage variation of sPGII levels 8 weeks after therapy for H pylori infection correlates with eradication. Additional studies are needed to confirm these results.

Gastric cancer screening by combined assay for serum anti-Helicobacter pylori IgG antibody and serum pepsinogen levels - "ABC method"

The current status of screening for gastric cancer-risk (gastritis A, B, C, D) method using combined assay for serum anti-Helicobacter pylori (Hp) IgG antibody and serum pepsinogen (PG) levels, "ABC method", was reviewed and the latest results of our ongoing trial are reported. It was performed using the following strategy: Subjects were classified into 1 of 4 risk groups based on the results of the two serologic tests, anti-Hp IgG antibody titers and the PG I and II levels: Group A [Hp(-)PG(-)], infection-free subjects; Group B [Hp(+)PG(-)], chronic atrophic gastritis (CAG) free or mild; Group C [Hp(+)PG(+)], CAG; Group D [Hp(-)PG(+)]), severe CAG with extensive intestinal metaplasia. Continuous endoscopic follow-up examinations are required to detect early stages of gastric cancer. Asymptomatic Group A, which accounts for 50-80% of all the subjects may be excluded from the secondary endoscopic examination, from the viewpoint of efficiency. Hp-infected subjects should be administered eradication treatment aimed at the prevention of gastric cancer.

The role of serum pepsinogen and gastrin test for the detection of gastric cancer in Korea

BACKGROUND AND AIM

This study was performed to determine whether serum pepsinogen (PG) and gastrin testing can be used to detect gastric cancer in Korea.

METHODS

Serum levels of PG I (sPGI) and sPGII, PG I/II ratios, and gastrin levels were measured in 1006 patients with gastroduodenal diseases including cancer. Follow-up tests were performed 1 year after Helicobacter pylori eradication.

RESULTS

sPGI and sPGII levels increased and PG I/II ratios decreased in line with the severity of activity, chronic inflammation, and the presence of H. pylori (p < .01). In contrast, sPGI levels and PG I/II ratios decreased in proportion with the severity of atrophic gastritis (AG)/intestinal metaplasia (p < .01). Gastrin levels were found to be correlated with chronic inflammation negatively in the antrum but positively in the corpus. H. pylori eradication reduced sPGI, sPGII, and gastrin levels, and increased PG I/II ratios to the levels of H. pylori-negative patients, and was found to be correlated with reductions in activity and chronic inflammation of gastritis. The sensitivity and specificity of a PG I/II ratio of < or = 3.0 for the detection of dysplasia or cancer were 55.8-62.3% and 61%, respectively. In addition, sPGI and sPGII levels of intestinal-type cancer were significantly lower than those of the diffuse type, respectively (p = .008 and p = .05, respectively). Gastric cancer risk was highest in the H. pylori-positive, low PGI/II ratio (< or = 3.0) group with an odds ratio of 5.52 (confidence interval: 2.83-10.77).

CONCLUSION

PG I/II ratio (< or = 3.0) was found to be a reliable marker for the detection of dysplasia or gastric cancer, especially of the intestinal type. This detection power of PG I/II ratio (< or = 3.0) significantly increased in the presence of H. pylori, and thus, provides a means of selecting those at high risk of developing gastric cancer in Korea.

Problem of distinguishing false-positive tests from acute or transient Helicobacter pylori infections

BACKGROUND

Reliable detection of acute Helicobacter pylori infections remains problematic. The high prevalence of false-positive non-invasive tests in low H. pylori prevalence populations makes identification of acute and transient infections difficult.

METHODS

We explored the use of serum pepsinogens (PG) for diagnosis of acute infection in patients following H. pylori challenge such that the onset of the infection was known. We then compared those findings to a group of children with presumed acute infections defined as a positive urea breath test (UBT) and negative IgG serology.

RESULTS

We examined the pattern and calculated cut-off values of PG levels in 18 adult volunteers with known acute H. pylori infection. We then compared the results with sera from nine symptomatic children with presumed acute H. pylori infection and a matched control group of nine children who did not meet criteria for acute H. pylori infection. In acute infection, both PGI and II levels increased following H. pylori infection reaching a peak by 2 weeks post-infection. The frequency of a positive test defined as a value > mean +2 SD was 17, 71, and 94% at week 1, 2, and 4 post-infection, respectively. Only one child with presumed acute H. pylori infection had an elevated serum PGI and one had an elevated PGII. Five of the children had follow-up UBTs and four were negative consistent with the diagnosis of false-positive UBT. H. pylori infection was confirmed in the child with an elevated PGI level.

CONCLUSIONS

These data suggest that a single positive noninvasive test in populations of low prevalence is most likely a false-positive result. This suggests that a single positive test requires confirmation preferably using a test that measures a different parameter (e.g., UBT confirmed by stool antigen test). It appears that most "transient"H. pylori infections are diagnosed on the basis of false-positive tests. PG levels are possible candidates as the confirmatory test.

Helicobacter pylori infection: a protective factor for esophageal squamous cell carcinoma in a Taiwanese population

AIM

Many researchers have reported the inverse relationship between Helicobacter pylori (H. pylori) infection and esophageal adenocarcinoma risk, but very few studies have examined the association between H. pylori infection and the development of esophageal squamous-cell carcinoma (ESCC). Therefore, the aim of this study is to evaluate the relationship between H. pylori infection and ESCC risk.

METHOD

Subjects were cancer cases, pathologically proven to have ESCC, in two large medical centers in Kaohsiung metropolitan of southern Taiwan between August 2000 and May 2003. Controls were from the healthy subjects who lived in Kaohsiung metropolitan and voluntarily participated in one large multiyear of gene-environmental study. In total, 127 cases (116 males and 11 females) and 171 controls (161 males and 10 females) were recruited in the same period of time for interviews. H. pylori seropositivity was determined by an enzyme-linked immunosorbant assay measuring IgG.

RESULTS

A total of 28 (22.1%) and 74 (43.3%) out of 127 cases and 171 controls, respectively, had positive H. pylori infection. After adjusting for other covariates, subjects with positive H. pylori infections had a significantly reduced risk (adjusted odds ratio (AOR) = 0.51; 95% CI = 0.27-0.96; p= 0.037) of developing ESCC than those without. This result was even more pronounced in the groups of younger subjects, nonsmokers, or nondrinkers. In addition, among the 117 cancer patients who provided information about site of cancer lesion, the present study found that subjects with cancer lesions in the lower third of the esophagus had significantly fewer positive H. pylori infections (AOR = 0.34; 95% CI = 0.14-0.80; p= 0.013) than controls.

CONCLUSION

Our findings suggest that H. pylori infection may protect against the development of ESCC. Additional studies are needed to confirm these findings.

Improvement in serum pepsinogens and gastrin in long-term monitoring after eradication of Helicobacter pylori: comparison with H. pylori-negative patients

BACKGROUND

A decrease in pepsinogen and gastrin levels 1-3 months after Helicobacter pylori eradication is well known. However, few data are available on the long-term progression of these decreases beyond 1 year after eradication, and there has been no investigation into whether pepsinogen and gastrin levels return to normal levels as defined by data from H. pylori-negative patients with dyspepsia.

AIM

We studied the effect of H. pylori eradication on pepsinogen and gastrin levels for more than 1 year, and compared levels to those in H. pylori-negative patients with dyspepsia. We also investigated the effect of H. pylori eradication on the course of atrophic corpus gastritis as reflected by histology, and on PGI levels and PG I/II ratio.

METHODS

We enrolled 172 H. pylori-positive patients with dyspepsia who had undergone successful eradication therapy of more than 1 year's duration and 101 non-treated H. pylori-negative patients with dyspepsia. H. pylori status was assessed at entry and at each endoscopy after eradication by culture, histological results, the rapid urease test and the urea breath test. In both groups, patients were evaluated for fasting serum pepsinogen I and II and gastrin using a radioimmunoassay technique, and underwent detailed histological assessment according to the updated Sydney System.

RESULTS

In the H. pylori-negative patients, mean serum pepsinogen I and II, I/II ratio and gastrin levels were 52.6 +/- 20.8 ng/mL, 9.2 +/- 4.2 ng/mL, 6.0 +/- 1.7 and 53.5 +/- 29.2 pg/mL, respectively. In H. pylori-positive patients with long-term eradication, pepsinogen I and II, I/II ratio and gastrin levels were 81.3 +/- 46.6 ng/mL, 25.9 +/- 17.1 ng/mL, 3.4 +/- 1.3 and 131.9 +/- 130.8 pg/mL, respectively, before treatment. At 1-3 months after eradication, serum pepsinogen I and II levels in the H. pylori-positive patients decreased to levels similar to those in the negative patients, whereas pepsinogen I/II ratio and gastrin levels remained lower and higher, respectively, than in the negative patients. Serum pepsinogen I/II ratio and gastrin levels then became similar between the groups at 12-15 months after eradication. In histological findings, inflammation and neutrophil activity decreased by 1-3 months, and atrophy in the corpus and metaplasia in the antrum decreased by 12-15 months.

CONCLUSION

The results suggest that atrophic corpus gastritis and superficial gastritis are reversible, as indicated by both histological and serological findings in a long-term follow-up study.

Serum IL-8 as a possible marker for determining the status of Helicobacter pylori infection in patients with untreated and treated peptic ulcer

Failure to eradicate Helicobacter pylori can lead to peptic ulcer recurrence and gastric malignancy. Therefore, the objective of this study was to develop a noninvasive method for determining whether H. pylori infection was eradicated with antibiotic-based triple therapy. A total of 17 patients with duodenal ulcer (DU) and 17 with gastric ulcer (GU) were evaluated both before and after treatment. Outcomes included serum levels of interleukin-8 (IL-8), pepsinogen I, and gastrin, and the Wilcoxon signed rank test was used to test significance. Changes in these parameters were also correlated with disease status. In those patients where both GU and DU healing occurred as a result of treatment, most showed an increase in serum IL-8 and a decrease in serum pepsinogen. Serum gastrin levels were not significantly changed in either group. Posttreatment increases in serum IL-8 were seen in 15 of 17 (88%) recovered DU patients and 14 of 17 (82%) recovered GU patients (P<.05 for each). Posttreatment decreases in pepsinogen I were found in 15 of 17 DU and 15 of 17 GU patients (P<.05 for each). These preliminary findings suggest that an increase in serum IL-8 and possibly a decrease in pepsinogen I may be useful in identifying the successful eradication of H. pylori infection in patients with peptic ulcer treated with antibiotics. A more systematic analysis of these putative diagnostic markers is now warranted.

[Basal concentrations of gastrin and pepsinogen I and II in gastric ulcer: influence of Helicobacter pylori infection and usefulness in the control of the eradication]

AIM

To study the influence of Helicobacter pylori eradication on basal gastrin and pepsinogen I and II levels in patients with gastric ulcer over a 1-year follow-up period, and to assess the usefulness of these values in confirming H. pylori eradication after treatment.

METHODS

Fifty-six patients with gastric ulcer and H. pylori infection were prospectively studied. At the beginning of the study, endoscopy with biopsies for histologic examination and urease testing was carried out, as were 13C-urea breath test and blood samples for determination of gastrin and pepsinogen I and II values by radioimmunoassay and serology. Histologic study, 13C-urea breath test and laboratory determinations were repeated at months 1, 6 and 12 after completion of eradication treatment.

RESULTS

H. pylori infection was eradicated in 82.1% of patients. In patients with successful H. pylori eradication, the initial mean gastrin value was 75.5 +/- 39.1 pg/ml, while at 1 month after treatment this value decreased to 49.2 +/- 21 pg/ml (p < 0.0001). No further reductions were noted. Initial pepsinogen I and II values were 104 +/- 58 and 15.8 +/- 10 ng/ml, respectively, whereas at month 1 after treatment these values were 77 +/- 42 and 7.3 +/- 4 ng/ml, respectively (p < 0.0001) and were 72 +/- 41 and 6.7 +/- 3 ng/ml respectively at month 6 (p < 0.01); no further variations were observed thereafter. The area under the ROC curve which reveals eradication through reductions in hormonal values was 0.70 for gastrin, 0.78 for pepsinogen I, 0.93 for pepsinogen II and 0.92 for the pepsinogen I/II ratio. At months 6 and 12 after treatment completion, differences in mean gastrin and pepsinogen I and II values between the patients with normal histologic findings and those with chronic gastritis were significant (p < 0.05).

CONCLUSIONS

a) H. pylori eradication is associated with an early fall in basal gastrin values and a progressive decrease in basal pepsinogen I and II values. b) In patients with gastric ulcer, determination of the decrease in basal pepsinogen II levels is a useful and early non-invasive method for confirming eradication. c) Determination of gastrin and pepsinogen I and II values may be useful for assessing improvement in gastritis 6 months after treatment completion.

Helicobacter pylori

H. pylori infection is now recognized as causing serious and life threatening disease in 20% to 30% of those infected. Reliable therapy is problematic. This article addresses the current approach to diagnosis and therapy and new considerations regarding whom to treat. The emphasis of the association of the gastric cancer phenotype of H. pylori infection (cagA positive H. pylori corpus gastritis) and protection against gastroesophageal reflux disease is an example of epidemiology without regard to the biology. Improvements in health and diet and an increase in body mass have accompanied the natural loss of H. pylori from the population. The search for virulence factors to help direct therapy to those who would most benefit has, to date, proved fruitless. Whenever H. pylori is diagnosed, it should be treated.

Helicobacter pylori infection in asymptomatic children: comparison of diagnostic tests

BACKGROUND

Childhood is known to be a major risk period for acquiring Helicobacter pylori infection. Studies of the epidemiology of H. pylori infection depend on the validity of the diagnostic tools used to detect the infection in the pediatric setting. This study aims to conduct a combination of diagnostic tests on the same children, evaluate the sensitivity and the specificity of IgG antibody testing compared with the 13C-urea breath test, and examine the variability in the prevalence of H. pylori infection in asymptomatic children based on the use of different diagnostic tests.

METHODS

13C-urea breath test (13C-UBT), whole blood FlexSure (systemic antibodies), and OraSure (salivary antibodies) tests were conducted on 287 asymptomatic children (151 boys, 136 girls; ages 2-18 years). The three tests were conducted on each child during the same day. The prevalence was calculated using each test independently.

RESULTS

H. pylori infection was detected in 32%, 22%, or 18% of the studied children, based on UBT, OraSure, or FlexSure, respectively. A total of 103 children tested positive for any one test (92 on UBT, 8 on FlexSure, 3 on OraSure), giving a prevalence of 35% based on the "parallel" method. Only 39 children tested positive in all three tests, giving a prevalence of 14% based on the "serial" method. Using the UBT as the gold standard, the sensitivity of FlexSure and OraSure were 48% and 65%, respectively, and the specificity of both tests was greater than 95%. When we applied the parallel method, the sensitivity and specificity of the combined antibody tests (FlexSure + OraSure) compared to the UBT were 71% and 95%, respectively.

CONCLUSIONS

Among asymptomatic children, there is a wide variation in the prevalence of H. pylori infection based on the diagnostic test used. The study shows that antibody assays are less suitable than the UBT. However, under certain conditions, the IgG assays (combined systemic, salivary, or both) are less expensive alternative tools to the UBT for epidemiological studies in children.