13C-urea breath test to diagnose Helicobacter pylori infection in children aged up to 6 years

No association between Helicobacter pylori infection and gastrointestinal complaints in a large cohort of symptomatic children

AIM

This Polish study estimated the prevalence of the Helicobacter pylori infection in symptomatic children aged 3-18 and investigated its association with gastrointestinal complaints.

METHODS

We prospectively enrolled 1984 children (54% female) with a mean age of 9.5 ± 4.1 years, from Silesia, Poland, for the Good Diagnosis Treatment Life screening programme from 2009 to 2016. They underwent a ¹³ C-isotope-labelled urea breath test (UBT) to assess their Helicobacter pylori status, making this the biggest Polish study to use this approach. Further analysis included parental-reported gastrointestinal symptoms and standard deviation scores (SDS) of anthropometric measurements.

RESULTS

The Helicobacter pylori infection was identified in 220 (11%) children (48% female) and was independent of age and sex. The frequency of symptoms did not differ between Helicobacter positive and negative children (all p > 0.05). Children with a positive UBT result had a lower body mass SDS (-0.41 ± 0.98 versus -0.26 ± 1.01, p = 0.04) and height SDS (-0.45 ± 1.34 versus -0.23 ± 1.27, p = 0.02), but similar body mass index SDS.

CONCLUSION

We found a low prevalence of Helicobacter pylori in symptomatic children, and positive UBT results were not associated with symptoms that suggested Helicobacter pylori infections. Our findings support the 2017 European and North American guidelines for Helicobacter infections in children.

[Diagnosis of Helicobacter pylori Infection]

Accurate diagnosis of Helicobacter pylori (H. pylori) infection is mandatory for the effective management of many gastroduodenal diseases. Currently, various diagnostic methods are available for detecting these infections, and the choice of method should take into account the clinical condition, accessibility, advantage, disadvantage, as well as cost-effectiveness. The diagnostic methods are divided into invasive (endoscopic-based) and non-invasive methods. Non-invasive methods included urea breath test, stool antigen test, serology, and molecular methods. Invasive methods included endoscopic imaging, rapid urease test, histology, culture, and molecular methods. In this article, we provide a review of the currently available options and recent advances of various diagnostic methods.

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.

Prevalência de infecção por Helicobacter pylori em uma comunidade indígena em São Paulo e fatores associados: estudo transversalPrevalence of Helicobacter pylori infection in an indigenous community in São Paulo and associated factors: cross-sectional study

CONTEXT AND OBJECTIVE:

The prevalence of Helicobacter pylori infection is unevenly distributed among different populations. The aim here was to evaluate the factors associated with Helicobacter pylori infection among children up to five years of age living in a high-risk community.

DESIGN AND SETTING:

Cross-sectional study in an indigenous community of Guarani Mbya ethnicity, Tekoa Ytu and Tekoa Pyau villages, Jaraguá district, city of São Paulo (SP), Brazil.

METHODS:

74 children aged 0.4 to 4.9 years (mean 2.9 ± 1.3 years; median 3.1), and 145 family members (86 siblings, 43 mothers and 16 fathers) were evaluated for Helicobacter pylori infection using the validated 13C-urea breath test. Clinical and demographic data were collected.

RESULTS:

The prevalence was 8.3% among children aged 1-2 years and reached 64.3% among those aged 4-5 years (P = 0.018; overall 31.1%). The prevalence was 76.7% among siblings and 89.8% among parents. There was a negative association with previous use of antibiotics in multivariate analysis adjusted for age (odds ratio, OR: 0.07; 95% confidence interval, CI: 0.01 to 0.66; P = 0.02). The prevalence was higher among males (OR: 1.55), and was associated with maternal infection (OR: 1.81), infection of both parents (OR: 1.5), vomiting (OR: 1.28), intestinal parasitosis (OR: 2.25), previous hospitalization (OR: 0.69) and breastfeeding (OR: 1.87).

CONCLUSIONS:

The prevalence was high among subjects older than three years of age, thus suggesting that the incidence of infection was higher over the first three years of life. Previous use of antibiotics was inversely associated with current Helicobacter pylori infection.

DIAGNOSTIC ACCURACY OF UREA BREATH TEST FOR HELICOBACTER PYLORI INFECTION IN CHILDREN WITH DYSPEPSIA IN COMPARISON TO HISTOPATHOLOGY

ABSTRACT Background - Helicobacter pylori infection is the gram negative bacillus with the close association with chronic antral gastritis. Objective - In this study, we evaluate the accuracy of urea breath test (UBT) with carbon isotope 13 in comparison with histopathology of gastric antrum for detection of H. pylori infection in children with dyspepsia. Methods - This cross-sectional study was performed at specialized laboratory of Shiraz Gastroenterohepatology Research Center and Nemazee Hospital, Iran, during a 12-months period. This study investigated the sensitivity, specificity, and positive and negative predictive values of UBT in comparison with biopsy-based tests. We included a consecutive selection of 60 children who fulfilled Rome III criteria for dyspepsia. All children were referred for performing UBT with carbon isotope 13 (C13) as well as endoscopy. Biopsies were taken from antrum of stomach and duodenum. The pathologic diagnosis was considered as the standard test. Results - The mean age of the participants was 10.1±2.6 (range 7-17 years). From our total 60 patients, 28 (46.7%) had positive UBT results and 32 (53.3%) had negative UBT results. Pathologic report of 16 (57.1%) out of 28 patients who had positive UBT were positive for H. pylori and 12 (42.9%) ones were negative. Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Conclusion - Sensitivity and specificity of C13-UBT for detection of H. pylori infection were 76.2% and 69.2% respectively. Another multicenter study from our country is recommended.

Evaluation of Exalenz Bioscience's BreathID for Helicobacter pylori detection

Carbon-labeled urea breath tests, which have high sensitivity and specificity, are the preferred method used in epidemiological studies, screening dyspeptic patients and assessing eradication or recurrence of Helicobacter pylori infection. The principle of the (13)C-urea breath test relies upon the ability of the H. pylori urease to hydrolyze the orally administered (13)C-urea. The BreathID (Exalenz Bioscience Inc., Union, NJ, USA) provides a competitive solution for breath testing, including unique features such as automatic continuous breath collection and analysis. This is an unattended convenient test, with no human error as the correct part of the breath is collected and patients' assistance is not required. The test results are available in real time at the point of care and enable shortened breath testing procedures. Additionally, several studies showing expanded utility of the BreathID in pediatrics, after therapy and during proton pump inhibitors intake, further support the safety and performance of the BreathID in the diagnosis of H. pylori.

Low dose capsule based 13c-urea breath test compared with the conventional 13c-urea breath test and invasive tests

CONTEXT

One of the limitations of 13C-urea breath test for Helicobacter pylori infection diagnosis in Brazil is the substrate acquisition in capsule presentation.

OBJECTIVES

The purpose of this study was to evaluate a capsule-based 13C-urea, manipulated by the Pharmacy Division, for the clinical practice.

METHODS

Fifty patients underwent the conventional and the capsule breath test. Samples were collected at the baseline and after 10, 20 and 30 minutes of 13C-urea ingestion. Urease and histology were used as gold standard in 83 patients.

RESULTS

In a total of 50 patients, 17 were positive with the conventional 13C-urea (75 mg) breath test at 10, 20 and 30 minutes. When these patients repeated breath test with capsule (50 mg), 17 were positive at 20 minutes and 15 at 10 and 30 minutes. The relative sensitivity of 13C-urea with capsule was 100% at 20 minutes and 88.24% at 10 and at 30 minutes. The relative specificity was 100% at all time intervals. Among 83 patients that underwent capsule breath test and endoscopy the capsule breath test presented 100% of sensitivity and specificity.

CONCLUSIONS

Capsule based breath test with 50 mg 13C-urea at twenty minutes was found highly sensitive and specific for the clinical setting.

Helicobacter pylori infection - recent developments in diagnosis

Considering the recommended indications for Helicobacter pylori (H. pylori) eradication therapy and the broad spectrum of available diagnostic methods, a reliable diagnosis is mandatory both before and after eradication therapy. Only highly accurate tests should be used in clinical practice, and the sensitivity and specificity of an adequate test should exceed 90%. The choice of tests should take into account clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy and the availability of the tests. This review concerns some of the most recent developments in diagnostic methods of H. pylori infection, namely the contribution of novel endoscopic evaluation methodologies for the diagnosis of H. pylori infection, such as magnifying endoscopy techniques and chromoendoscopy. In addition, the diagnostic contribution of histology and the urea breath test was explored recently in specific clinical settings and patient groups. Recent studies recommend enhancing the number of biopsy fragments for the rapid urease test. Bacterial culture from the gastric biopsy is the gold standard technique, and is recommended for antibiotic susceptibility test. Serology is used for initial screening and the stool antigen test is particularly used when the urea breath test is not available, while molecular methods have gained attention mostly for detecting antibiotic resistance.

Diagnosis of Helicobacter pylori infection by means of reduced-dose ¹³C-urea breath test and early sampling of exhaled breath

OBJECTIVE

The aim of this study was to evaluate the accuracy of reduced-dose ¹³C-urea breath test (¹³C-UBT) and early sampling of exhaled breath for the detection of Helicobacter pylori infection in children and adolescents.

METHODS

Patients up to 20 years old that underwent upper gastrointestinal endoscopy with gastric biopsies were included. The ¹³C-UBT was performed after a 4-hour fasting period with 4 points of collection: baseline (T₀), and at 10, 20, and 30 minutes (T₁₀, T₂₀, and T₃₀) after ingestion of 25 mg ¹³C-urea diluted in 100 mL of apple juice. The infection status was defined through 3 invasive methods, and a patient was considered infected with a positive culture or concomitant positive histology and rapid urease test. The absence of infection was defined by all negative histology, rapid urease test, and culture. Analysis of exhaled breath samples was performed with an isotope-selective infrared spectrometer. A receiver-operating characteristic curve analysis was done to define cutoff delta over baseline (DOB) values.

RESULTS

A total of 129 patients between the ages of 2.1 and 19 years (median 11.6 years; mean age ± standard deviation 11.5 ± 3.8 years; F:M 85:44) were included. The prevalence of infection was 41.1%. The sensitivity (S) and specificity (Sp) were at T₁₀ (cutoff DOB 2.55‰), S 94.7% (95% confidence interval [CI] 90.9-98.5) and Sp 96.8% (95% CI 93.4-100); at T₂₀ (DOB 2.5‰), S 96.2% (95% CI 92.9-99.5) and Sp 96.1% (95% CI 93.7-99.8); and at T₃₀ (DOB 1.6‰), S 96.2% (95% CI 92.9-99.5) and Sp 94.7% (95% CI 90.8-98.6).

CONCLUSIONS

Low-dose ¹³C-UBT with early sampling is accurate for diagnosing H pylori infection in children and adolescents.

13C-urea breath test for the diagnosis of Helicobacter pylori infection in children: a systematic review and meta-analysis

BACKGROUND

The (13) C-urea breath test ((13) C-UBT) is a safe, noninvasive and reliable method for diagnosing H. pylori infection in adults. However, the test has shown variable accuracy in the pediatric population, especially in young children. We aimed to carry out a systematic review and meta-analysis to evaluate the performance of the (13) C-UBT diagnostic test for H. pylori infection in children.

METHODS

We conducted a systematic review of the PubMed, Embase and Liliacs databases including studies from January 1998 to May 2009. Selection criteria included studies with at least 30 children and reporting the comparison of (13) C-UBT against a gold standard for H. pylori diagnosis. Thirty-one articles and 135 studies were included for analysis. Children were stratified in subgroups of <6 and ≥6 years of age, and we considered variables such as type of meal, cutoff value, tracer dose, and delta time for the analysis.

DISCUSSION

The (13) C-UBT performance meta-analyses showed 1, good accuracy in all ages combined (sensitivity 95.9%, specificity 95.7%, LR+ 17.4, LR- 0.06, diagnostic odds ratio (DOR) 424.9), 2, high accuracy in children >6 years (sensitivity 96.6%, specificity 97.7%, LR+ 42.6, LR- 0.04, DOR 1042.7), 3, greater variability in accuracy estimates and on average a few percentage points lower, particularly specificity, in children ≤6 years (sensitivity 95%, specificity 93.5%, LR+ 11.7, LR- 0.12, DOR 224.8). Therefore, the meta-analysis shows that the (13) C-UBT test is less accurate for the diagnosis of H. pylori infection in young children, but adjusting cutoff value, pretest meal, and urea dose, this accuracy can be improved.

Evidence-based guidelines from ESPGHAN and NASPGHAN for Helicobacter pylori infection in children

OBJECTIVE

As the clinical implications of Helicobacter pylori infection in children and adolescents continue to evolve, ESPGHAN and NASPGHAN jointly renewed clinical guidelines using a standardized evidence-based approach to develop updated recommendations for children and adolescents in North America and Europe.

METHODS

An international panel of 11 pediatric gastroenterologists, 2 epidemiologists, 1 microbiologist, and 1 pathologist was selected by societies that developed evidence-based guidelines based on the Delphi process with anonymous voting in a final face-to-face meeting. A systematic literature search was performed on 8 databases of relevance including publications from January 2000 to December 2009. After excluding nonrelevant publications, tables of evidence were constructed for different focus areas according to the Oxford classification. Statements and recommendations were formulated in the following areas: whom to test, how to test, whom to treat, and how to treat. Grades of evidence were assigned to each recommendation based on the GRADE system.

RESULTS

A total of 2290 publications were identified, from which 738 were finally reviewed. A total of 21 recommendations were generated, and an algorithm was proposed by the joint committee providing evidence-based guidelines on the diagnostic workup and treatment of children with H pylori infection.

CONCLUSIONS

These clinical practice guidelines represent updated, best-available evidence and are meant for children and adolescents living in Europe and North America, but they may not apply to those living on other continents, particularly in developing countries with a high H pylori infection rate and limited health care resources.

Age and gender differences in urea breath test results

BACKGROUND

(13) C urea breath test (UBT) results, used for the diagnosis of Helicobacter pylori infection, fluctuate in different age groups. We characterized both the age- and gender-based trends of UBT results, from early childhood through late adulthood.

METHODS

A national H. pylori referral laboratory was screened for all positive UBTs during 2007-2008, determined as a delta over baseline (DOB) ≥ 3·5. Data were analysed with respect to both age and gender.

RESULTS

In the studied period, 61,060 UBTs were performed and 24,237 were positive. After excluding multiple testing for an individual, a total of 21,767 positive results were analysed. The male/female ratio for positive UBTs was 1 : 1·77. DOB results decreased as age increased from a maximum of 38·6 ± 21 at age 3-5 years to 21·1 ± 12 at age 19-30 in females (P < 0·001) and from 30·0 ± 16 at age 6-10 years to 14·7 ± 8 at age 19-30 years in males (P < 0·0001). At this point, the values reached a nadir for both genders. In patients older than 60 years, old test results increased moderately (P < 0·003). In all age groups, except 6-10 years old, females had significantly higher UBT results than males.

CONCLUSIONS

The decrease in mean UBT values already occurs during the first decade of life, and results increase following the sixth decade. Females have significantly higher results than males even in early childhood and throughout old age.

Validation of a monoclonal stool antigen test for diagnosing Helicobacter pylori infection in young children

BACKGROUND AND OBJECTIVE

The monoclonal stool antigen test for diagnosing Helicobacter pylori infection in children has been tested in developed countries, showing sensitivity and specificity higher than 90%. However, its accuracy in young children from developing countries is not well established. The aim of the study was to determine the accuracy of the monoclonal stool antigen test for diagnosing H pylori infection in children up to 7 years old.

PATIENTS AND METHODS

Two hundred seventy-six patients (53.6% female; ages 0.35-6.99 years) were evaluated. Gold standard positive culture or positive histology and rapid urease tests were performed. The test (Amplified IDEIATM Hp StAR) was done according to the manufacturer's instructions. Results were expressed as optical density (OD) and an OD more than or equal to 0.190 was considered positive. Additionally, a receiver operating characteristic curve was used to find the best cutoff.

RESULTS

The monoclonal stool antigen test for diagnosing H pylori infection showed 100% sensitivity (95% confidence interval [CI] 92.7%-100%) and 76.2% specificity (95% CI 70.1%-81.4%), considering the manufacturer's cutoff. After setting a new cutoff with the receiver operating characteristic curve (OD = 0.400), sensitivity remained 100% (95% CI 92.7%-100%), but the specificity improved to 97.7% (95% CI 94.7%-99%). At ages up to 2 years, sensitivity was 100% (95% CI 43.8%-100%) and specificity was 100% (95% CI 92.4%-100%); at ages 2 to 4 years, 100% (95% CI 80.6%-100%) and 97.6% (95% CI 96%-99.2%); at ages older than 4 years, 100% (95% CI 88.6%-100%) and 96.6% (95% CI 94.7%-98%), respectively.

CONCLUSIONS

The monoclonal stool antigen test is accurate for diagnosing H pylori in children younger than 7 years old, but it must be locally validated in order to find the best cutoff for each population.

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.

Antibiotics taken for other illnesses and spontaneous clearance of Helicobacter pylori infection in children

PURPOSE

Factors that determine persistence of untreated Helicobacter pylori (H. pylori) infection in childhood are not well understood. We estimated risk differences for the effect of incidental antibiotic exposure on the probability of a detected clearance at the next test after an initial detected H. pylori infection.

METHODS

The Pasitos Cohort Study (1998-2005) investigated predictors of H. pylori infection in children from El Paso, Texas, and Juarez, Mexico. Children were screened for infection at 6-month target intervals from 6 to 84 months of age, using the 13C-urea breath test corrected for body-size-dependent variation in CO2 production. Exposure was defined as courses of any systemic antibiotic (systemic) or those with anti-H. pylori action (HP-effective) reported for the interval between initial detected infection and next test. Binomial regression models included country of residence, mother's education, adequacy of prenatal care, age at infection, and interval between tests.

RESULTS

Of 205 children with a test result and antibiotic data following a detected infection, the number of children who took > or =1 course in the interval between tests was 74 for systemic and 33 for HP-effective. The proportion testing negative at the next test was 66% for 0 courses, 72% for > or =1 systemic course, and 79% for > or =1 HP-effective course. Adjusted risk differences (95%CI) for apparent clearance, comparing > or =1 to 0 courses were 10% (1-20%) for systemic and 11% (0-21%) for HP-effective.

CONCLUSIONS

Incidental antibiotic exposure appears to influence the duration of childhood H. pylori infection but seems to explain only a small portion of spontaneous clearance.

Urea breath test in children: the United States prospective, multicenter study

BACKGROUND

The urea breath test (UBT) is generally considered the gold standard for the diagnosis of Helicobacter pylori infections in adults.

GOALS

To investigate the utility and accuracy of urea breath testing in children from the United States.

METHODS

Children scheduled to undergo upper gastrointestinal endoscopy for various clinical symptoms underwent a 13C-UBT using the US standard protocol for adults. Results were compared with rapid urease testing (RUT), culture, and histology. H. pylori positivity was defined according to the FDA, Division of Anti-Infective Drug Products criteria, i.e. positive culture and/or positive RUT and histology. H. pylori negativity was defined as all tests negative. Results were evaluated by delta over baseline (DOB) and urea hydrolysis rate (UHR).

RESULTS

A total of 176 children from five centers were evaluated; 48 were infected. Compared to the defined standard, the results with the UBT based on delta over baseline (DOB) cut-off value (positive: > or = 2.4 per thousand) showed that the sensitivity and specificity of the UBT were 97.9% and 96.1%, respectively. Based on the UHR cut-off value (positive: > or = 10.0 microg/min), the sensitivity and specificity were 95.8% and 99.2%. In young children (2- to 5-year olds), sensitivity and specificity of UHR method were higher than the DOB method (100% and 100% vs 100% and 82.4%, respectively).

CONCLUSION

The US standard (13)C-UBT proved to be both simple and accurate for the diagnosis of H. pylori infections in children. The UHR method to calculate of (13)C-UBT result provided excellent results for children of all ages.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Does the diagnostic accuracy of the 13C-urea breath test vary with age even after the application of urea hydrolysis rate?

BACKGROUND

Endogenous CO(2) production may be a possible explanation for higher false-positive results reported for (13)C-urea breath test (UBT) in children below 6 years. In this study, we evaluated whether age affects the diagnostic accuracy of the (13)C-UBT even after the application of urea hydrolysis rate (UHR) in children.

METHODS

A total of 612 (13)C-UBTs and endoscopic biopsies were performed on children divided into two groups; children under 6 years (n = 126) and children aged 6-18 years (n = 486). For (13)C-UBT, 75 mg (13)C-urea was ingested, and breath sample was collected 30 minutes later. Delta over baseline (DOB) was determined, and UHR was calculated to normalize the DOB values for endogenous CO(2) production.

RESULTS

There was significant difference between the DOB values of children under 6 years and those of children over 6 years in H. pylori-positive (p = .029) and -negative groups (p = .002). On applying the UHR, no significant difference was observed between the UHR values of children under 6 years and those of children over 6 years in H. pylori-positive (p = .877) and -negative groups (p = .427). In 12.6% children under 6 years, false-positive results were observed on applying the DOB, and in 9.0% on applying the UHR (p = .125).

CONCLUSIONS

The (13)C-UBT is a noninvasive method exhibiting high diagnostic accuracy with both UHR as well as DOB. However, high false-positive results for (13)C-UBT were noted in children below 6 years on applying both UHR as well as DOB. Thus, this may not only be due to the effects of endogenous CO(2) production but also due to other factors.

More economic 25 mg 13C-urea breath test can be effective in detecting primary Helicobacter pylori infection in children

BACKGROUND AND AIM

The high cost of the 13C-urea breath test (UBT) limits its wide application for both epidemiological and clinical studies for diagnosing Helicobacter pylori infection. This study examined if a lower-dose UBT, applying 1 mg/kg of bodyweight (maximum 25 mg, UBT(25)), could introduce cost savings while preserving high diagnostic yields for primary H. pylori infection.

METHODS

Children aged less than 16 years were recruited after obtaining consent. Those children with administration of antibiotics or proton pump inhibitors within 1 month of the tests were excluded. Positive tests for both the UBT with 50 mg urea (UBT(50)) and the H. pylori stool antigen (HpSA) were qualifying criteria for H. pylori infection. Negative results for both indicated non-infection. The UBT(25) was conducted 1 week after the UBT(50). The cut-off points for the UBT(25) ranging from 2delta to 5delta were examined for their sensitivity, specificity and accuracy rates.

RESULTS

A total of 153 children were recruited (55% male; mean age 9.1 +/- 3.5 years). Both the UBT(50) and HpSA test were positive in 18 (13.1%) and negative in 119 children, respectively. The sensitivity and specificity of the UBT(25) were optimally achieved at 88.9% (95% confidence interval [CI]: 71.4-100) and 95.0% (95% CI: 91.1-99.9), judged with a cut-off point at 3.5delta. The diagnostic accuracy was significantly higher for children older than 7 years than for those younger than 7 years (98%vs 85%, P = 0.009).

CONCLUSION

Lower-dose UBT titration by bodyweight can cut costs while maintaining a highly reliable method to screen primary H. pylori infection in children older than 7 years, which is generally beyond school age.

Sensitivity and specificity of various tests for the diagnosis of Helicobacter pylori in Egyptian children

OBJECTIVES

Many noninvasive methods (using breath, blood, and stool samples) are available to diagnose Helicobacter pylori. However, because the noninvasive tests are proxy measures of the infection, they need validation before use. Factors that may affect test validity include patient age, gender, and geographic location. Because no data were available on the validation of noninvasive tests for the diagnosis of H. pylori among children in the Middle East, this study was performed.

METHODS

Children between 2 and 17 years of age evaluated at the Cairo University School of Medicine pediatric gastroenterology clinic who were already scheduled for upper endoscopy were eligible for enrollment in the study. At the time of endoscopy, 3 biopsies were collected and used for rapid urease, histology, and culture, respectively. All children also donated a sample of stool and blood and had a urea breath test performed. Stool and serum samples were tested for the presence of H. pylori by using commercially available enzyme-linked immunosorbent assay-based technology. The sensitivity, specificity, and positive and negative predictive values were calculated for each noninvasive test used in the study. Receiver operating curves also were charted to determine optimal cut points for the various tests when used in the current study cohort.

RESULTS

One hundred eight children were enrolled in the study, with 52 children being under 6 years of age. The urea breath test and HpStar (DakoCytomation, Norden, Denmark) stool enzyme-linked immunosorbent assay kit had the highest sensitivity and specificity (sensitivity and specificity: 98 and 89 [urea breath test] and 94 and 81 [HpStar], respectively), whereas the serologic kit had an unacceptably low sensitivity (50%). The sensitivity of neither the urea breath test nor the HpStar tests was affected by subject age, but specificity of the HpStar test, although still high, was significantly lower among children under 6 years. Receiver operating curves found optimal cut points of the urea breath test at 6.2 delta over baseline and of the HpStar at 0.25 enzyme-linked immunosorbent assay units.

CONCLUSION

The urea breath test and HpSTAR stool antigen kit are reliable tests for the noninvasive diagnosis of H. pylori among children living in the Middle East.

Furazolidone-based triple therapy for H pylori gastritis in children

AIM: To evaluate the furazolidone-based triple therapy in children with symptomatic H pylori gastritis.

METHODS: A prospective and consecutive open trial was carried out. The study included 38 patients with upper digestive symptoms sufficiently severe to warrant endoscopic investigation. H pylori status was defined based both on histology and on positive ¹³C-urea breath test. Drug regimen was a seven-day course of omeprazole, clarithromycin and furazolidone (100 mg, 200 mg if over 30 kg) twice daily. Eradication of H pylori was assessed two months after treatment by histology and ¹³C-urea breath test. Further clinical evaluation was performed 7 d, 2 and 6 mo after the treatment.

RESULTS: Thirty-eight patients (24 females, 14 males) were included. Their age ranged from 4 to 17.8 (mean 10.9 ± 3.7) years. On intent-to-treat analysis (n = 38), the eradication rate of H pylori was 73.7% (95% CI, 65.2%-82%) whereas in per-protocol analysis (n = 33) it was 84.8% (95% CI, 78.5%-91%). All the patients with duodenal ulcer (n = 7) were successfully treated (100% vs 56.2% with antral nodularity). Side effects were reported in 26 patients (68.4%), mainly vomiting (14/26) and abdominal pain (n = 13). Successfully treated dyspeptic patients showed improvement in 78.9% of H pylori-negative patients after six months and in 50% of H pylori-positive patients after six months of treatment.

CONCLUSION: Triple therapy with furazolidone achieves moderate efficacy in H pylori treatment. The eradication rate seems to be higher in patients with duodenal ulcer.

[Breath tests in the diagnosis of gastrointestinal diseases]

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

Dynamics of Helicobacter pylori infection in a US-Mexico cohort during the first two years of life

BACKGROUND

The Pasitos Cohort Study has followed children in El Paso, Texas and Ciudad Juarez, Mexico since 1998 to identify determinants of Helicobacter pylori infection. This paper describes patterns of acquisition and elimination of H. pylori infection in 468 children from birth to 24 months.

METHODS

Mothers were recruited during pregnancy at maternal-child clinics; children were targeted for follow-up examinations every 6 months after birth. H. pylori infection was detected using the 13C-urea breath test, corrected for age-dependent variation in CO2 production.

RESULTS

Test results were available for 359, 341, 269, and 215 children around target ages of 6, 12, 18, and 24 months, respectively. The person-time at risk of a first detectable infection was 7742 person-months; 128 first infections were detected, thus the incidence rate was 1.7% per month (95% confidence interval 1.4-2.0%). Rates were similar in boys and girls and on both sides of the border; evidence suggests, however, that this similarity could be due to selection bias. Among children with follow-up after a positive test, 77% tested negative at a later visit.

CONCLUSIONS

The initial acquisition of detectable H. pylori infection occurred at a rate of 20% per year among Pasitos Cohort children from birth to 24 months of age. A key finding, with implications for clinical, community health, and research settings, is that most of these infections did not persist. The transient nature of early H. pylori infection should be considered when designing research or contemplating therapeutic intervention for this age group.

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

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

Diagnosis of Helicobacter pylori infection

While there are some attempts to improve culture of Helicobacter pylori, molecular methods have been the main focus of this interest. Their main application concerns the development of rapid tests also allowing the determination of bacterial resistance, i.e. real-time polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH), or to genotype the strains. Attempts to improve, simplify or explain the discrepancies of urea breath test results have been made and new generation of stool antigen test with monoclonal antibodies either using the standard ELISA format or rapid immunoenzymatic detection have confirmed their value. With regard to serology, studies have mainly focused on the distinction of infections with more pathogenic strains and the ability to diagnose atrophic gastritis with the Gastropanel.

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