Diagnostic accuracy of tests for Helicobacter pylori in an Alaska Native population

Urea breath test for Helicobacter pylori infection in adult dyspeptic patients: A meta-analysis of diagnostic test accuracy

BACKGROUND

Helicobacter pylori (H. pylori) infection has been well-established as a significant risk factor for several gastrointestinal disorders. The urea breath test (UBT) has emerged as a leading non-invasive method for detecting H. pylori. Despite numerous studies confirming its substantial accuracy, the reliability of UBT results is often compromised by inherent limitations. These findings underscore the need for a rigorous statistical synthesis to clarify and reconcile the diagnostic accuracy of the UBT for the diagnosis of H. pylori infection.

AIM

To determine and compare the diagnostic accuracy of 13C-UBT and 14C-UBT for H. pylori infection in adult patients with dyspepsia.

METHODS

We conducted an independent search of the PubMed/MEDLINE, EMBASE, and Cochrane Central databases until April 2022. Our search included diagnostic accuracy studies that evaluated at least one of the index tests (13C-UBT or 14C-UBT) against a reference standard. We used the QUADAS-2 tool to assess the methodological quality of the studies. We utilized the bivariate random-effects model to calculate sensitivity, specificity, positive and negative test likelihood ratios (LR+ and LR-), as well as the diagnostic odds ratio (DOR), and their 95% confidence intervals. We conducted subgroup analyses based on urea dosing, time after urea administration, and assessment technique. To investigate a possible threshold effect, we conducted Spearman correlation analysis, and we generated summary receiver operating characteristic (SROC) curves to assess heterogeneity. Finally, we visually inspected a funnel plot and used Egger's test to evaluate publication bias.

RESULTS

The titles and abstracts of 4621 studies were screened; 79 articles were retrieved and selected for full-text reading. Finally, 60 studies were included in the diagnostic test accuracy meta-analysis. Our analysis demonstrates superior diagnostic accuracy of 13C-UBT over 14C-UBT, indicated by higher sensitivity (96.60% vs 96.15%), specificity (96.93% vs 89.84%), likelihood ratios (LR+ 22.00 vs 10.10; LR- 0.05 vs 0.06), and area under the curve (AUC; 0.979 vs 0.968). Notably, 13C-UBT's DOR (586.47) significantly outperforms 14C-UBT (DOR 226.50), making it the preferred diagnostic tool for dyspeptic individuals with H. pylori infection. Correlation analysis revealed no threshold effect (13C-UBT: r = 0.48; 14C-UBT: r = -0.01), and SROC curves showed consistent accuracy. Both 13C-UBT and 14C-UBT showed high AUC values (13C-UBT 0.979; 14C-UBT 0.968) near 1.00, reinforcing their excellent accuracy and endorsing both as reliable diagnostic tools in clinical practice.

CONCLUSION

In summary, our study has demonstrated that 13C-UBT has been found to outperform the 14C-UBT, making it the preferred diagnostic approach. Additionally, our results emphasize the significance of carefully considering urea dosage, assessment timing, and measurement techniques for both tests to enhance diagnostic precision. Nevertheless, it is crucial for researchers and clinicians to evaluate the strengths and limitations of our findings before implementing them in practice.

Systematic Review and Meta-Analysis on the Sensitivity and Specificity of 13C/14C-Urea Breath Tests in the Diagnosis of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) continues to be a major health problem worldwide, causing considerable morbidity and mortality due to peptic ulcer disease and gastric cancer. The aim of the present systematic review and meta-analysis was to determine the sensitivity and specificity of 13C/14C-urea breath tests in the diagnosis of H. pylori infection. A PRISMA systematic search appraisal and meta-analysis were conducted. A systematic literature search of PubMed, Web of Science, EMBASE, Scopus, and Google Scholar was conducted up to August 2022. Generic, methodological and statistical data were extracted from the eligible studies, which reported the sensitivity and specificity of 13C/14C-urea breath tests in the diagnosis of H. pylori infection. A random effect meta-analysis was conducted on crude sensitivity and specificity of 13C/14C-urea breath test rates. Heterogeneity was assessed by Cochran’s Q and I2 tests. The literature search yielded a total of 5267 studies. Of them, 41 articles were included in the final analysis, with a sample size ranging from 50 to 21857. The sensitivity and specificity of 13C/14C-urea breath tests in the diagnosis of H. pylori infection ranged between 64−100% and 60.5−100%, respectively. The current meta-analysis showed that the sensitivity points of estimate were 92.5% and 87.6%, according to the fixed and random models, respectively. In addition, the specificity points of estimate were 89.9% and 84.8%, according to the fixed and random models, respectively. There was high heterogeneity among the studies (I2 = 98.128 and 98.516 for the sensitivity and specificity, respectively, p-value < 0.001). The 13C/14C-urea breath tests are highly sensitive and specific for the diagnosis of H. pylori infection.

Helicobacter pylori Prevalence and Risk Factors in Three Rural Indigenous Communities of Northern Arizona

Helicobacter pylori (H. pylori) is one of the most common bacterial stomach infections and is implicated in a majority of non-cardia gastric cancer. While gastric cancer has decreased in the United States (US), the incidence in the Navajo Nation is nearly four times higher than surrounding Non-Hispanic White populations. Little is known about H. pylori prevalence in this population or other Indigenous communities in the lower 48 states. In this cross-sectional study, 101 adults representing 73 households from three Navajo Nation chapter communities completed surveys and a urea breath test for active H. pylori. Accounting for intrahousehold correlation, H. pylori prevalence was 56.4% (95% CI, 45.4–66.8) and 72% of households had at least one infected person. The odds of having an active infection in households using unregulated water were 8.85 (95% CI, 1.50–53.38) that of the use of regulated water, and males had 3.26 (95% CI, 1.05–10.07) higher odds than female. The prevalence of H. pylori in Navajo is similar to that seen in Alaska Natives. Further investigation into factors associated with prevention of infection is needed as well as understanding barriers to screening and treatment.

Risk factors for atrophic gastritis in the Japanese young and middle-aged: a study using double-contrast upper gastrointestinal barium X-ray radiography

PURPOSE

To identify risk factors for atrophic gastritis in Japanese young and middle-age subjects by double-contrast upper gastrointestinal barium X-ray radiography (UGI-XR).

MATERIALS AND METHODS

We included 351 consecutive Japanese subjects (158 males, 193 females; age 25-49 years, mean 44 years) seen between October 2014 and March 2016. All underwent serum Helicobacter pylori (Hp) antibody- and UGI-XR examinations. Two radiologists independently recorded their UGI-XR findings of atrophic gastritis (AG). Interobserver agreement was assessed by calculating the kappa (κ) coefficient. Univariate and multivariate analyses were performed to investigate the association between AG and the subjects' gender, smoking habit, alcohol intake, body mass index, and Hp infection.

RESULTS

AG was diagnosed in 85 subjects (24%) on UGI-XR images; interobserver agreement was good (κ = 0.745). By univariate analysis, the male gender and a high serum Hp titer (IgG ≥ 10 U/ml) were significantly association with AG (p < 0.05). Multivariate analysis revealed that a high serum Hp titer was the only independent, significant factor (p < 0.05). The odds ratio for a high serum Hp titer was 128 (95% CI, 54.8-498.4).

CONCLUSION

Our UGI-XR study indicated that Hp infection was significantly associated with AG in Japanese young and middle-aged subjects.

Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti-Helicobacter pylori IgG antibodies

BACKGROUND

Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti- H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection.

METHODS

A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti- H. pylori IgG antibodies; a UBT was administered to participants > 5 years old.

RESULTS

We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti- H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age ≥ 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered.

CONCLUSIONS

Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity.

Helicobacter pylori infection in subjects negative for high titer serum antibody

AIM

To investigate the clinicopathological features of the patients testing negative for high titer serum anti-Helicobacter pylori (H. pylori) antibody.

METHODS

The antibody titers were measured using antigens derived from Japanese individuals. ¹³C-urea breath test-positive individuals were defined as having H. pylori infection. We investigated the demographic characteristics, laboratory data, endoscopic findings including Kyoto classification of gastritis, and histology in negative-high titer patients without H. pylori eradication therapy. Kyoto classification consisted of scores for gastric atrophy, intestinal metaplasia, enlarged folds, nodularity, and redness.

RESULTS

Of the 136 subjects enrolled, 23 (17%) had H. pylori infection. Kyoto classification had an excellent area under the receiver operating characteristics curve (0.886, 95% confidence interval: 0.803-0.968, P = 3.7 × 10^-20) for predicting H. pylori infection with a cut-off value of 2. Further, Kyoto classification, H. pylori density, and neutrophil activity had high accuracies (89.7%, 96.3%, and 94.1%, respectively). Kyoto classification was independent of the demographic and laboratory parameters in multivariate analysis.

CONCLUSION

Endoscopic Kyoto classification of gastritis is a useful predictor of H. pylori infection in negative-high titer antibody patients.

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.

Prevalence and Risk Factors for Helicobacter Pylori Infection among Healthy Inhabitants in Northern Jakarta, Indonesia

Background: The prevalence of Helicobacter pylori (H. pylori) infection in Indonesia has been reported to be exceedingly low. The purpose of our study was to confirm whether this is the case in Northern Jakarta using a sensitive 13C-urea breath test (UBT), and to examine any associations with lifestyle/environment factors and potential routes of transmission. Methods: We recruited a total of 196 subjects from a low-income community in Northern Jakarta, Indonesia, data from 193 who completed a questionnaire about their lifestyle/environment and had UBT being included as the final. Odds ratios (ORs) adjusted for sex and age with 95% confidence intervals (CIs) were calculated using a logistic regression model. Results: The overall H. pylori infection rate was 15.0% (95%CI, 10.3-20.9), with variation among Javanese (9.1%, total=77), Buginese (40.0%, 35), Betawi (9.1%, 33), Sundanese (3.7%, 27), and Batak (40.0%, 5). On multivariate analysis, the ORs for intake of soybean milk, cucumber more than once a week, infrequent hand washing practice before meals, and alcohol consumption were 0.10 (95%CI: 0.01-0.97), 6.61 (95%CI: 1.87-23.3), 4.10 (95%CI: 1.15-14.6), and 61.9 (95%CI: 1.67-2300.8), respectively. Rates for Buginese (OR=7.84; 95%CI: 1.82-33.8) and Batak (OR=20.1; 95%CI: 1.90-213.2) were significantly higher than for Javanese. Conclusions: The H. pylori infection rate in this study was relatively low, in line with previous studies. Regarding ethnicity factors, Buginese and Batak reported eating food using fingers more frequently than Javanese, Betawi, and Sundanese. Our study indicated that person-person transmission is possible in this low prevalence area. The low infection rates for H. pylori among Javanese, Betawi, and Sundanese ethnics could be partly due to their sanitary practices.

Antisecretory medication is associated with decreased Helicobacter pylori detection in gastric marginal zone lymphoma

Helicobacter pylori status influences the prognosis and management of gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), so accurate determination of H pylori status is of clinical importance. The low rate of histologic H pylori positivity among gastric MALT lymphoma cases at our institution prompted investigation for possible causes. A case series of 24 patients as having gastric MALT lymphoma (with no diffuse large B-cell component) in a tertiary care setting between 1997 and 2010 was identified, and clinical records were reviewed. Immunohistochemical staining for H pylori and BCL10 was performed. This study received institutional review board approval (protocol number M13-033). Thirty-nine percent of cases (9/23) were H pylori positive by histology, and 4 additional patients had positive serologic results; overall, 57% of cases (13/23) were positive for H pylori. Treatment with antisecretory medications was associated with a lower likelihood of histologic positivity (13% among treated patients vs 75% among untreated; P = .04). Nuclear localization of BCL10 was seen in 2 cases and was not associated with H pylori status. Antisecretory medications decrease the likelihood of histologic detection of H pylori in gastric MALT lymphoma cases. Incorporation of results of serologic or other testing is needed to ensure correct classification with respect to H pylori status.

Accuracy of urea breath test in Helicobacter pylori infection: Meta-analysis

AIM: To quantitatively summarize and appraise the available evidence of urea breath test (UBT) use to diagnose Helicobacter pylori (H. pylori) infection in patients with dyspepsia and provide pooled diagnostic accuracy measures.

METHODS: We searched MEDLINE, EMBASE, Cochrane library and other databases for studies addressing the value of UBT in the diagnosis of H. pylori infection. We included cross-sectional studies that evaluated the diagnostic accuracy of UBT in adult patients with dyspeptic symptoms. Risk of bias was assessed using QUADAS (Quality Assessment of Diagnostic Accuracy Studies)-2 tool. Diagnostic accuracy measures were pooled using the random-effects model. Subgroup analysis was conducted by UBT type (¹³C vs¹⁴C) and by measurement technique (Infrared spectrometry vs Isotope Ratio Mass Spectrometry).

RESULTS: Out of 1380 studies identified, only 23 met the eligibility criteria. Fourteen studies (61%) evaluated ¹³C UBT and 9 studies (39%) evaluated ¹⁴C UBT. There was significant variation in the type of reference standard tests used across studies.Pooled sensitivity was 0.96 (95%CI: 0.95-0.97) andpooled specificity was 0.93 (95%CI: 0.91-0.94). Likelihood ratio for a positive test was 12 and for a negative test was 0.05 with an area under thecurve of 0.985. Meta-analyses were associated with a significant statistical heterogeneity that remained unexplained after subgroup analysis. The included studies had a moderate risk of bias.

CONCLUSION: UBT has high diagnostic accuracy for detecting H. pylori infection in patients with dyspepsia. The reliability of diagnostic meta-analytic estimates however is limited by significant heterogeneity.

The prevalence of Helicobacter pylori is decreasing in Iranian patients

AIM

The objective of this study was to evaluate the time trend of Helicobacter pylori (H. pylori) prevalence and presence of intestinal Metaplasia over the period of seven years among gastritis Iranian patients.

BACKGROUND

H. pylori is the major causal factor in chronic gastritis. Its acquisition leads to a chronic, usually lifelong, inflammation of the gastric mucosa, which may gradually progress to atrophy with intestinal metaplasia in a significant proportion of infected individuals.

PATIENTS AND METHODS

H. pylori and intestinal Metaplasia data among 14,860 consecutive gastritis patients, who referred to the gastrointestinal department of Tehran's Taleghani Hospital in Iran from 2008 to 2014, was examined by sex and age group. The patients were divided into six age groups (16-30, 30-40, 40-50, 50-60 and >70). The chi-square test was used to compare the qualitative variables.

RESULTS

The overall prevalence rate among patient with H. pylori infection was 83.5% (12406/14860) and 11,394 (84.1%) of them were related to the gastritis. The prevalence rate of H. pylori among patient with severe gastritis was significantly higher (P<0.05) compared to mild and moderate gastritis. In addition, the prevalence of H. pylori decreased with age and has been declined in recent years. The presence of intestinal metaplasia increased with age (P<0.05).

CONCLUSION

The results of this study showed that the prevalence of H. pylori infection in Iranian population has been declined in recent years; nevertheless it seems to be highly prevalent in Iran. We also find a significant positive relationship between H. pylori infection and gastritis. There is no association between sex and infection, however in contrast with the most studies its prevalence decreased with age.

Gastric Helicobacter pylori infection associated with risk of diabetes mellitus, but not prediabetes

BACKGROUNDS AND AIM

The association between Helicobacter pylori infection and diabetes was inconsistent in previous studies. Moreover, there are no studies on the relationship between H. pylori infection and prediabetes in the literature. The aim of this study is thus to assess the association of Helicobacter infection, diagnosed by pathology from gastric biopsy, with diabetes and prediabetes.

METHODS

This cross-sectional study included 1285 subjects aged 19-85 who underwent esophagogastroduodenoscopy and gastric biopsy during health examinations at National Cheng Kung University Hospital from 2000 to 2009. Subjects were divided into three groups, including normal glucose tolerance, prediabetes, and diabetes. Diabetes and prediabetes were assessed according to the American Diabetes Association diagnostic criteria. Gastric Helicobacter infection was an independent variable. Chi-square tests, analysis of variance, and multinomial logistic regression models were used to analyze the effects of Helicobacter infection on the risk of diabetes and prediabetes while controlling for age, lifestyle, pathological conditions, and laboratory variables.

RESULTS

There were significant differences in the prevalence of gastric Helicobacter infection among the three groups. The results of multivariate analysis showed that age, obesity, family history of diabetes, hypertension, and hypertriglyceridemia were significantly related to both prediabetes and diabetes. Helicobacter pylori infection was positively associated with diabetes (odds ratio [OR] 1.42, 95% confidence interval [CI] 1.01-2.01), but not prediabetes (OR 1.02, 95% CI 0.77-1.36), in addition to male gender, education level (≤ 9 vs > 12 years), pre-hypertension, and low high-density lipoprotein cholesterol.

CONCLUSIONS

Gastric H. pylori infection is associated with diabetes, but not prediabetes.

Carbon-13 urea breath test for Helicobacter pylori infection in patients with uninvestigated ulcer-like dyspepsia: an evidence-based analysis

BACKGROUND

Dyspepsia is a condition defined by chronic pain or discomfort in the upper gastrointestinal tract that can be caused by Helicobacter pylori. The carbon-13 urea breath test (¹³C UBT) is a non-invasive test to detect H. pylori.

OBJECTIVES

We aimed to determine the diagnostic accuracy and clinical utility of the ¹³C UBT in adult patients with ulcer-like dyspepsia who have no alarm features.

DATA SOURCES

A literature search was performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid Embase, the Wiley Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published between 2003 and 2012.

REVIEW METHODS

We abstracted the sensitivity and specificity, which were calculated against a composite reference standard. Summary estimates were obtained using bivariate random effects regression analysis.

RESULTS

From 19 diagnostic studies, the ¹³C UBT summary estimates were 98.1% (95% confidence interval [CI], 96.3-99.0) for sensitivity and 95.1% (95% CI, 90.3-97.6) for specificity. In 6 studies that compared the ¹³C UBT with serology, the 1¹³C UBT sensitivity was 95.0% (95% CI, 90.1-97.5) and specificity was 91.6 % (95% CI, 81.3-96.4). The sensitivity and specificity for serology were 92.9% (95% CI, 82.6-97.3) and 71.1% (95% CI, 63.8-77.5), respectively. In 1 RCT, symptom resolution, medication use, and physician visits were similar among the ¹³C UBT, serology, gastroscopy, or empirical treatment arms. However, patients tested with ¹³C UBT reported higher dyspepsia-specific quality of life scores.

LIMITATIONS

Processing of the ¹³C UBT results can vary according to many factors. Further, the studies showed significant heterogeneity and used different composite reference standards.

CONCLUSIONS

The ¹³C UBT is an accurate test with high sensitivity and specificity. Compared with serology, it has higher specificity. There is a paucity of data on the ¹³C UBT beyond test accuracy.

PLAIN LANGUAGE SUMMARY

Breath test for detecting bacteria in patients with ulcer-like symptoms. Dyspepsia is a condition that causes long-term pain or discomfort in the upper abdomen. Symptoms can include heartburn, burping, bloating, nausea, or slow digestion. Dyspepsia can be caused by a bacterium that also causes ulcers and stomach cancer. Half of the world's people are believed to be infected with these bacteria. A test has been developed to detect the bacteria in a breath sample. Our review determined the accuracy of this breath test in adults with ulcer-like symptoms. From 19 studies, the breath test correctly identified 98% of patients with the bacteria and 95% of patients without the bacteria, as determined by a reference standard. Six studies compared the breath test to a blood test that is currently used. Both the breath and blood tests performed well in correctly identifying patients with the bacteria. However, the blood test was incorrectly positive in 20 more patients who did not have the bacteria according to the breath test. This means that more patients would have received unnecessary treatment. Thus, the breath test is an accurate test to detect the bacteria in adult patients who have ulcer-like symptoms. But the many differences among the studies in our review included several steps taken to perform the breath test and the reference standards used to compare a blood test with the breath test.

The Prevalence of Helicobacter pylori Infection Decreases with Older Age in Atrophic Gastritis

The clinical pathological characteristics of 3969 adult patients with chronic atrophic gastritis were retrospectively studied. The positivity of intestinal metaplasia and dysplasia in atrophic gastric specimens increased with age; however, H. pylori positivity and inflammatory activity decreased significantly with increased age. H. pylori infection was present in 21.01% of chronic atrophic gastritis patients, and 92.33% of the subjects with H. pylori infection were found to have simultaneous inflammatory activity. The intestinal metaplasia and dysplasia positivity markedly increased as the degree of gastric atrophy increased. In conclusion, the incidence of H. pylori infection decreased with age and correlated significantly with inflammatory activity in atrophic gastritis patients. The intestinal metaplasia and dysplasia positivity notably increased as the degree of gastric atrophy increased. Large population-based prospective studies are needed to better understand the progression of CAG.

Association between Helicobacter pylori infection detected by the (13) C-urea breath test and low serum ferritin levels among Japanese adults

BACKGROUND

Helicobacter pylori infection is a major risk factor for chronic gastritis, digestive ulcers, and gastric cancer. Previous studies have shown associations between H. pylori infection and decreased iron storage. Therefore, this study aimed to examine the associations between H. pylori infection and serum iron and ferritin levels in Japan.

MATERIALS AND METHODS

Overall, 268 Japanese individuals who visited a clinic located in an urban area for H. pylori infection tests and subsequent eradication were enrolled. H. pylori infection was diagnosed by a (13) C-urea breath test, with positive results defined as values ≥2.5‰.

RESULTS

The overall infection rate was 65.3% (175/268). The geometric mean serum iron levels in uninfected and infected subjects were 115.7 μg/dL and 108.9 μg/dL, respectively, in men, and 83.9 and 91.8 μg/dL, respectively, in women. The geometric mean serum ferritin levels were 128.9 and 81.0 ng/mL, respectively, in men, and 25.5 and 27.0 ng/mL, respectively, in women. Regression analysis adjusted for age showed that lower geometric mean serum ferritin levels were significantly associated with H. pylori infection in men (131.8 vs 79.4 ng/mL p = .009) and in women (33.9 vs 23.4 ng/mL p = .041). The difference was greater in subjects ≥50 years old, although the interaction was not statistically significant. Helicobacter pylori infection was not significantly associated with serum iron levels.

CONCLUSION

This study showed that H. pylori infection was significantly associated with altered serum ferritin levels in Japanese individuals, particularly in those aged ≥50 years.

Prevalence of Helicobacter pylori in a First Nations population in northwestern Ontario

OBJECTIVE

To assess prevalence of Helicobacter pylori infection, reasons for referral for gastroscopy, and clinical findings of gastroscopy in a symptomatic First Nations population in northwestern Ontario from 2009 to 2011.

DESIGN

Three hundred four hospital charts of symptomatic patients who underwent upper endoscopy between June 2009 and March 2011 were reviewed.

SETTING

Meno Ya Win Health Centre in Sioux Lookout, Ont.

PARTICIPANTS

First Nations patients with dyspepsia undergoing gastroscopy.

MAIN OUTCOME MEASURES

Reason for referral, and clinical and histologic findings on gastroscopy.

RESULTS

The most common reasons for referral for gastroscopy were dyspepsia (59.2%) and undiagnosed anemia (18.1%). Overall, 66.8% of patients underwent biopsies; 37.9% of these patients tested positive for H pylori. Gastritis was encountered the most often, in 46.1% of patients; gastric ulcers in 6.9% of patients; and normal gastric mucosa was seen 36.8% of the time. The rate of H pylori infection is higher than in urban Canadian populations, but lower than in previous aboriginal prevalence estimates, particularly those based on seroprevalence values.

CONCLUSION

This study raises the clinical question of how eradication testing and treatment protocols should be addressed in remote regions with high disease prevalence. As more is learned about the role H pylori infection plays in serious gastrointestinal diseases, rural and aboriginal populations might need a special focus on testing availability and treatment close to home.

Alaska sentinel surveillance study of Helicobacter pylori isolates from Alaska Native persons from 2000 to 2008

Helicobacter pylori infection is more common in Alaska Native persons than in the general U.S. population, with seroprevalence to H. pylori approaching 75%. Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among H. pylori isolates. We analyzed H. pylori data from the Centers for Disease Control and Prevention's sentinel surveillance in Alaska from January 2000 to December 2008 to determine the proportion of culture-positive biopsy specimens with antimicrobial resistance from Alaska Native persons undergoing endoscopy. The aim of the present study was to monitor antimicrobial resistance of H. pylori isolates over time and by region in Alaska Native persons. Susceptibility testing of H. pylori isolates to metronidazole, clarithromycin, amoxicillin, and tetracycline was performed using agar dilution. Susceptibility testing for levofloxacin was performed by Etest. Overall, 45% (532/1,181) of persons undergoing upper endoscopy were culture positive for H. pylori. Metronidazole resistance was demonstrated in isolates from 222/531 (42%) persons, clarithromycin resistance in 159/531 (30%) persons, amoxicillin resistance in 10/531 (2%) persons, and levofloxacin resistance in 30/155 (19%) persons; no tetracycline resistance was documented. The prevalence of metronidazole, clarithromycin, and levofloxacin resistance varied by region. Female patients were more likely than male patients to demonstrate metronidazole (P < 0.05) and clarithromycin (P < 0.05) resistance. No substantial change in the proportion of persons with resistant isolates was observed over time. Resistance to metronidazole, clarithromycin, and levofloxacin is more common among H. pylori isolates from Alaska Native persons than those from elsewhere in the United States.