Diagnosis of Helicobacter pylori infection in a high-prevalence pediatric population: a comparison of 2 fecal antigen testing methods and serology

Comparison of Risk and Severity of Helicobacter Pylori Infection in Non-Native Versus US Native Pediatric Patients

Introduction

Helicobacter pylori (HP) infection is associated with gastritis, peptic ulcer disease (PUD) in the stomach and duodenum, and an increased risk of gastric cancer. The risk of infection, secondary symptoms, and negative outcomes is known to be increased in low- and middle-income countries and vastly less substantial in the United States and Europe. Current North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines recommend endoscopic diagnosis and susceptibility-guided therapy, which is not reflected by current adult guidelines for therapy. In this study, we complete a single-center retrospective review of HP risk by nativity status, as well as the results of the use of standard empiric therapy in HP and PUD patients.

Methods

We retrospectively reviewed all endoscopies with patients aged 1-21 years with a known nativity status and identified all HP diagnoses. We also completed the classification of Kyoto scores and classified patients as gastritis versus PUD. Treatment records were obtained, as well as downstream documentation of the impact of empiric therapy. HP prevalence and severity were compared between non-native and native US populations.

Results

In total 332 patients were identified, with 59 HP diagnoses. However, 64 patients were immigrants, and 268 were US natives. Totally 39.1% of all immigrant patients had an endoscopically identified HP infection, compared to only 12.7% of US native patients (P < 0.01, relative risk 3.07). HP severity was worse in immigrant patients (Kyoto score 1.5 versus 0.89; P = 0.008). Empiric high-dose amoxicillin triple therapy was equally effective in reducing symptoms in gastritis versus PUD patients.

Conclusions

Immigrant patients have a substantially higher risk and severity of HP infection than US natives. Empiric therapy remains highly effective at relieving symptoms. These findings in aggregate suggest that North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines may not adequately serve non-native pediatric patients, with an additional prospective multicenter study needed to confirm. In addition, a prospective study of treatment based on stool antigen tests, as well as a larger prospective study of empiric therapy, may suggest alterations to our approach in line with recent changes to adult Gastroenterology practice.

Epidemiology of Helicobacter pylori in Australia: a scoping review

Background

Helicobacter pylori (H. pylori), a bacterium implicated in the development of peptic ulcer and gastric cancer, is estimated to infect around half the world's population. Its prevalence in Australia is unclear. This scoping review aimed to evaluate all Australian literature providing estimates of the prevalence of H. pylori.

Methods

Australian studies examining H. pylori prevalence from 1982 onwards were eligible for inclusion. Medline, Embase and Scopus databases, and grey literature sources, were searched. Two independent reviewers undertook a two-stage screening process. Data were extracted by two independent reviewers using a pre-specified template.

Results

Of 444 identified studies, 75 were included in the review. H. pylori prevalence in Australian population-based studies (n = 8) ranged from 38.0% in 1991 to 15.1% in 2002; however, estimated prevalence across all non-clinical population studies in diverse sub-groups (n = 29) has varied dramatically. Decreased prevalence has been more marked in populations with gastrointestinal symptoms and conditions compared to non-clinical populations. Data on H. pyloriprevalence in vulnerable populations are lacking.

Conclusions

This is the first scoping review of Australian studies reporting H. pylori prevalence. A wide range of study designs, population groups, geographic regions, and diagnostic methods was included, involving data collected over a 50-year period (1969 to 2018). The summary of H. pylori prevalence estimates over time in this review points to a decrease in prevalence in Australia, particularly among populations with gastrointestinal symptoms and illnesses; however, it is unknown whether there is inequity in prevalence trends across vulnerable sub-groups of the Australian population. Future research and interventions supporting the health and wellbeing of vulnerable populations is required to ensure equitable health gains are made for all.

Prevalence and Risk Factors of Helicobacter pylori Infection among Children Aged 1 to 15 Years at Holy Innocents Children's Hospital, Mbarara, South Western Uganda

Background

Helicobacter pylori infection affects more than half of the world's population. The infection is generally acquired during childhood but can remain asymptomatic, with long-term clinical sequelae including gastritis, peptic ulcer disease, and stomach cancer.

Methods

The study was approved by Institutional Review Committee of Mbarara University of Science and Technology. After obtaining informed consent from parents/legal guardians, illegible children who presented with gastrointestinal complaints at Holy Innocents Children's Hospital were recruited; structured questionnaires were administered to the parents/guardians to collect information on sociodemographic data and risk factors of H. pylori infection. Four (4) millilitres of blood was collected from each child and tested for H. pylori blood Antibody test and stool specimens were used for H. pylori antigen test.

Results

The prevalence of H. pylori infection among the study participants was 24.3%. The infection rate increased with increase in age of the participants, from 16.2% among 1to 5 years old to 27.2% among 6 to 10 years. Infections were higher among school going children (68/74, p=0.003, OR 3.9; CI: 1.5 to 10.6) and children from crowded households (59/74, p<0.001, OR 2.6, and CI 1.3 to 5.0), unsafe source of drinking water at schools (46/74, p=0.003), and lack of sanitary facility at homes (57/74, p=0.001, and OR 1.6 CI 0.7 to 3.6).

Conclusion

The prevalence of H. pylori infection among children aged 1 to 15 years at Holy Innocents Children's Hospital was high and increases with age. School attendance, lack of sanitary facility, lack of safe drinking water, and overcrowding were the risk factors associated with H. pylori infection.

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.

Helicobacter pylori serology testing is a useful diagnostic screening tool for symptomatic inner city children

AIM

This study assessed the Helicobacter pylori (H. pylori) serum antibody test as a diagnostic screening tool in symptomatic inner city children.

METHODS

This was a retrospective study of patients aged one to 18 years who were referred to our paediatric gastroenterology department from 2009 to 2013. We included all patients who had H. pylori serum antibodies and/or faecal antigens who underwent esophagogastroduodenoscopy (EGD) for histology, with or without a gastric tissue rapid urease test.

RESULTS

A total of 395 patients had EGDs carried out to evaluate epigastric pain, heartburn and nausea or vomiting, and their overall socio-economic Z-score was -2.62. The histology was positive for H. pylori infection in 52 of 395 patients (13%), and epigastric pain was documented in 45 of these 52 patients (87%). Compared to histology, the serum H. pylori antibody test had a sensitivity of 88.4% and a specificity of 93.4%. The tissue rapid urease test and faecal antigen test had sensitivities of 89.3% and 55.6% and specificities of 89.9% and 98.9%, respectively.

CONCLUSION

The serum H. pylori antibody test had high sensitivity and specificity, and it was a good diagnostic screening tool in our study. Epigastric pain was strongly associated with a current H. pylori infection in our population.

Serum hepcidin levels in Helicobacter pylori-infected children with iron-deficiency anemia: a case-control study

Recently, hepcidin, an antimicrobial-like peptide hormone, has evolved as the master regulator of systemic iron homeostasis. Hepcidin integrates signals from diverse physiological inputs, forming a key connection between iron trafficking and response to infection. In this study, we aimed to investigate whether Helicobacter pylori infection modulates serum hepcidin level and response to oral iron therapy in children with iron-deficiency anemia. This was a case-control study including 60 children with iron-deficiency anemia (IDA; 30 H. pylori infected and 30 H. pylori noninfected) and 30 healthy children with comparable age and gender as the control group. Iron parameters including serum iron, ferritin, transferrin, total iron binding capacity, and transferrin saturation and serum hepcidin levels were assessed initially and after 3 months of oral iron therapy for IDA. Compared to the control group, serum hepcidin was significantly lower in H. pylori-noninfected children with IDA (P < 0.01) and significantly higher in H. pylori-infected children with IDA (P < 0.01). Hepcidin increased significantly in noninfected children with IDA after 3 months of oral iron therapy (P < 0.01). On the other hand, H. pylori-infected children showed nonsignificant change in hepcidin level after oral iron therapy (P > 0.05). Although hepcidin showed significant positive correlations with serum ferritin, hemoglobin (Hb), iron, and transferrin saturation in noninfected children with IDA (P < 0.01), it showed significant negative correlations with serum ferritin, Hb, iron, and transferrin saturation in H. pylori-infected children with IDA (P < 0.05). H. pylori infection upregulates serum hepcidin levels and was associated with diminished response to oral iron therapy in children with iron-deficiency anemia.

Effect of eradication of Helicobacter pylori in children with chronic immune thrombocytopenia: a prospective, controlled, multicenter study

BACKGROUND

The eradication of Helicobacter pylori has been associated with remission of immune thrombocytopenia (ITP) in approximately half of eradicated patients. Data on children are limited to small case series.

PROCEDURE

Children from 16 centers in Italy, who were less than 18 years of age and diagnosed with chronic ITP (cITP), were screened for H. pylori infection. Positive patients underwent standard triple therapy with amoxicillin, clarithromycin, and omeprazole. The eradication response was defined as follows: complete response, platelet (PLT) count ≥ 150 × 10(9) /L; partial response, PLT count of at least 50 × 10(9) /L; no response, PLT count <50 × 10(9) /L.

RESULTS

Of 244 screened patients, 50 (20%) had H. pylori infection, 37 of which received eradication therapy and completed follow-up. Eradication was successful in 33/37 patients (89%). PLT recovery was demonstrated in 13/33 patients after eradication (39%), whereas spontaneous remission was observed in 17/166 (10%) H. pylori-negative patients (P < 0.005). Responders more often required second line eradication (9/13), whereas a second cycle was required in 3/20 non-responders (P < 0.005).

CONCLUSIONS

Among the large cohort of patients, those who underwent successful H. pylori eradication showed a significantly higher PLT response. Therefore, it may be appropriate to look for H. pylori and eventually eradicate it in children with cITP.

Associations between Helicobacter pylori infection, co-morbid infections, gastrointestinal symptoms, and circulating cytokines in African children

BACKGROUND

Refugee children have complex medical needs and often have multiple infections. The relationship between infection, gastrointestinal symptoms, and systemic inflammation is poorly understood. We investigated these parameters in refugee children with a high prevalence of Helicobacter pylori, helminth, and malaria infection.

MATERIALS AND METHODS

African refugee children were recruited at resettlement health screening. Data were collected on demography, gastrointestinal symptoms, co-morbid infection, and serum for peripheral cytokine levels. Helicobacter pylori infection was diagnosed by a fecal-based immunoassay.

RESULTS

Data from 163 children were analyzed, of which 84.0% were positive for H. pylori. Infected children were significantly older (9.2 years +/- 3.7 vs 7.1 years +/- 3.9, p = .01). Half the cohort (84/163, 51.5%) described gastrointestinal symptoms but these were not strongly associated with co-morbid infections. Helicobacter pylori-infected children had significantly lower circulating log-interleukin-8 (IL-8) (odds ratio 0.61, 95% confidence interval (CI) 0.40, 0.94, p = .025). Helminth infections were common (75/163, 46%) and associated with elevated log-IL-5 (beta: 0.42, 95% CI 0.077, 0.76). Children with malaria (15/163, 9.2%) had elevated log-tumor necrosis factor-alpha (TNFalpha) and log-IL-10 (beta: 0.67, 95% CI 0.34, 1.0 and beta: 1.3, 95% CI 0.67, 1.9, respectively). IL-10 : IL-12 ratios were increased in H. pylori-infected children with malaria or helminth infections. Symptoms were generally not associated with levels of circulating peripheral cytokines irrespective of co-morbid infection diagnosis.

CONCLUSIONS

There is a high prevalence of asymptomatic H. pylori infection in recently resettled African refugee children. Gastrointestinal symptoms were not predictive of H. pylori nor of helminth infections. Serum cytokines, particularly IL-5, IL-10, and TNFalpha, were significantly elevated in children with malaria and helminth infections but not in those with H. pylori infection.

Helicobacter pylori diagnostic tests in children: review of the literature from 1999 to 2009

The array of tests that can be used for diagnosis of Helicobacter pylori infection is large, and it can be confusing to define which test to use particularly in children where results may not be comparable to those obtained in adult patients. Using PubMed, we reviewed the English literature from January 1999 to May 2009 to identify articles that determined sensitivity and specificity of H. pylori invasive and non-invasive diagnostic tests in children. We excluded articles that presented a review of the literature, abstracts, case reports, or series where children's results could not be separated from adult populations. Of the tissue based methods, rapid urease tests have better sensitivity than histology to detect presence of H. pylori; however, histology can detect the pathology associated with disease including gastritis, intestinal metaplasia, and other conditions that could be the cause of the child's symptoms. Culture of gastric tissues or stool has 100% specificity but sensitivity is low. Of the serologic tests, immunoblot has the best sensitivity. The urea breath tests have >75% sensitivity for detection of H. pylori before and after treatment. Immunoassays in stool using monoclonal antibodies have >95% sensitivity for detection of H. pylori before and after treatment. PCR testing can be performed in tissue and stool samples and can detect genes associated to antibiotic resistance. In summary, the current commercial non-invasive tests have adequate sensitivity and specificity for detecting the presence of H. pylori; however, endoscopy with histopathology is the only method that can detect H. pylori and lesions associated with the infection.

Improved performance of a rapid office-based stool test for detection of Helicobacter pylori in children before and after therapy

A modified version of a rapid office based one-step monoclonal immunoassay for detection of Helicobacter pylori antigen in stool samples from children was evaluated against biopsy specimen-based methods and compared to a monoclonal enzyme immunoassay using the same antigen. Blinded stool samples from 185 children (0.3 to 18.2 years) were investigated at the time of upper endoscopy prior to anti-H. pylori therapy; 62 children were H. pylori infected and 123 noninfected according to predefined reference standards. Samples obtained 6 to 8 weeks after anti-H. pylori therapy were available from 58 children (3.8 to 17.7 years) and were compared to results of the [(13)C]urea breath test (14/58 were positive). The rapid stool tests were performed by two independent readers. Of 243 rapid tests performed, 1 (0.4%) was invalid for technical reasons. Equivocal results (very weak line) were reported 16 times by reader 1 and 27 times by reader 2. When equivocal results were considered positive, the two observers agreed on 76 positive and 160 negative results and disagreed on 7 samples (2.9%). The sensitivity was 90.8% for reader 1 and 85.5% for reader 2, and the specificity was 91.0% and 93.4%, respectively. The monoclonal enzyme immunoassay revealed a sensitivity and specificity of 94.7% and 97.6%, respectively. The modified chromatographic immunoassay is a good alternative in settings or situations when the monoclonal enzyme immunoassay or the [(13)C]urea breath test are not available or feasible. In order to improve sensitivity, very weak lines should be considered positive test results.

Evaluation of Helicobacter pylori Immunoglobulin G (IgG), IgA, and IgM serologic testing compared to stool antigen testing

The utility of Helicobacter pylori serology was evaluated in 4,722 specimens and compared to stool antigen detection. Immunoglobulin M (IgM) sensitivity (6.8%) was unacceptably low. Key performance differences were observed in IgG specificity, IgA sensitivity, and specificity between adults and children that may warrant differentiating optimal serologic cutoff values by age.

Helicobacter pylori, helminth infections and growth: a cross-sectional study in a high prevalence population

AIM

Helicobacter pylori (H. pylori) infection is usually acquired in childhood and may adversely affect growth, although data are inconsistent. This study investigated growth parameters in a paediatric cohort with a high prevalence of H. pylori and helminth infection.

METHODS

A cross-sectional study of African refugee children (<16 years) recruited at their initial health assessment following resettlement in Australia. Detailed demographic, infection and anthropometric data were obtained. H. pylori infection was diagnosed by monoclonal faecal antigen enzyme immunoassay testing (MFAT). Growth restriction was defined as children with any anthropometric measures below the fifth centile for age and gender.

RESULTS

H. pylori infection was detected in 149/182 (81.9%). Children with H. pylori infection were older (mean 8.5 years, standard deviation (SD) 4.2 years vs. 5.8 years, SD 4.5 years, p < 0.001). No gender differences were observed. After adjustment for age, H. pylori did not adversely affect body mass index or other anthropometric measurements. Helminth infections were common (41.8%) but not associated with reduced growth or with H. pylori infection.

CONCLUSION

H. pylori and helminth infections are prevalent in African refugee children but neither is associated with growth restriction. Longitudinal growth velocity studies are necessary to identify any long-term consequences of H. pylori on childhood growth.

An insight into the relationships between hepcidin, anemia, infections and inflammatory cytokines in pediatric refugees: a cross-sectional study

BACKGROUND

Hepcidin, a key regulator of iron homeostasis, is increased in response to inflammation and some infections, but the in vivo role of hepcidin, particularly in children with iron deficiency anemia (IDA) is unclear. We investigated the relationships between hepcidin, cytokines and iron status in a pediatric population with a high prevalence of both anemia and co-morbid infections.

METHODOLOGY/PRINCIPAL FINDINGS

African refugee children <16 years were consecutively recruited at the initial post-resettlement health check with 181 children meeting inclusion criteria. Data on hematological parameters, cytokine levels and co-morbid infections (Helicobacter pylori, helminth and malaria) were obtained and urinary hepcidin assays performed. The primary outcome measure was urinary hepcidin levels in children with and without iron deficiency (ID) and/or ID anaemia (IDA). The secondary outcome measures included were the relationship between co-morbid infections and (i) ID and IDA, (ii) urinary hepcidin levels and (iii) cytokine levels. IDA was present in 25/181 (13.8%). Children with IDA had significantly lower hepcidin levels (IDA median hepcidin 0.14 nmol/mmol Cr (interquartile range 0.05-0.061) versus non-IDA 2.96 nmol/mmol Cr, (IQR 0.95-6.72), p<0.001). Hemoglobin, log-ferritin, iron, mean cell volume (MCV) and transferrin saturation were positively associated with log-hepcidin levels (log-ferritin beta coefficient (beta): 1.30, 95% CI 1.02 to 1.57) and transferrin was inversely associated (beta: -0.12, 95% CI -0.15 to -0.08). Cytokine levels (including IL-6) and co-morbid infections were not associated with IDA or hepcidin levels.

CONCLUSIONS/SIGNIFICANCE

This is the largest pediatric study of the in vivo associations between hepcidin, iron status and cytokines. Gastro-intestinal infections (H. pylori and helminths) did not elevate urinary hepcidin or IL-6 levels in refugee children, nor were they associated with IDA. Longitudinal and mechanistic studies of IDA will further elucidate the role of hepcidin in paediatric iron regulation.