Eficacia de la determinación fecal de Helicobacter pylori mediante la técnica HpSA en enfermos con hemorragia digestiva alta

Accuracy of the Helicobacter pylori diagnostic tests in patients with peptic ulcer bleeding: a systematic review and network meta-analysis

INTRODUCTION

Some studies suggest that the accuracy of Helicobacter pylori diagnostic tests is decreased in peptic ulcer bleeding (PUB). We aimed to assess the accuracy of diagnostic tests for H. pylori in patients with PUB in a diagnostic test accuracy (DTA) network meta-analysis.

METHODS

A systematic search was carried out in seven databases until November 2019. We collected or calculated true and false positive and negative values, and constructed 2×2 diagnostic contingency tables with reference standards including histology, rapid urease test, urea breath test, serology, stool antigen test, culture, and polymerase chain reaction. We ranked the index tests by the superiority indices (SI) and calculated pooled sensitivity and specificity of each test.

DISCUSSION

Our search yielded 40 eligible studies with 27 different diagnostic strategies for H. pylori. In 32 articles, the reference standard was a combination of multiple tests. In 12 studies, the index tests were compared with a single testing method. We analyzed seven networks with the reference standards against a single or a combination of diagnostic index tests. None of the index tests had better diagnostic accuracy (SI between 9.94 and 2.17) compared with the individual index tests as all the confidence intervals included 1. Combined testing strategies had higher sensitivities (0.92-0.62) and lower specificities (0.85-0.46) while single tests proved to have higher specificities (0.83-0.77) and lower sensitivities (0.73-0.42).

CONCLUSION

Use of combined tests may have a rationale in clinical practice due to their higher sensitivities. The differences between the included DTA studies limited the comparison of the testing strategies.

Non-variceal upper GI bleeding in patients already hospitalized for another condition

OBJECTIVES

To compare outpatients (OPs) presenting with non-variceal upper gastrointestinal bleeding (NVUGIB) to those who started hemorrhaging while in a hospital (inpatients, IPs) in a contemporary setting and to better identify predictors of outcome.

METHODS

Retrospective data from the Canadian Registry of Patients With Upper Gastrointestinal Bleeding Undergoing Endoscopy (RUGBE). Descriptive, inferential, and multivariate logistic regression models were carried out in 469 IPs (68.5+/-14 years, 36% women) and 1,395 OPs (65.5+/-18 years, 39% women) in 18 Canadian community and tertiary care centers.

RESULTS

Main outcomes were rebleeding, mortality, and their predictors. IPs differed from OPs in disease acuity (P=0.02) and comorbidities (3.1+/-1.7 vs. 2.3+/-1.5, P<0.001), and were admitted longer (7.2+/-7.4 vs. 5+/-5.4 days, P<0.001) and more often to intensive care unit (ICU; 40.5% vs. 16%, P<0.001). Ulcers or erosions predominated (83% vs. 85%, P=0.28), treated by endotherapy (38% vs. 36%, P=0.46). More IPs received proton pump inhibitors (PPIs; 88% vs. 83%, P=0.009). Mortality was greater for IPs (11% vs. 3.5%, P<0.001), but rebleeding (15.7% vs. 13.4%, P=0.23) and surgery (6.9% vs. 6.4%, P=0.72) were not. Among IPs, comorbidity (odds ratio, OR=1.15; 95% confidence interval, CI: 1.01-1.32) and endoscopic high-risk stigmata increased (OR=3.86, 95% CI:2.05-7.26), whereas PPI decreased (OR=0.20, 95% CI:0.10-0.42) rebleeding; high-risk stigmata (OR=3.13, 95% CI:1.23-7.99) and rebleeding (OR=4.19, 95% CI:2.06-8.55) increased mortality, whereas low disease acuity was protective (OR=0.20; 95% CI:0.46-0.90).

CONCLUSIONS

IPs are sicker than OPs. Endoscopic hemostasis and PPI therapy favorably affect rebleeding in IPs, whereas patient characteristics principally determine the threefold greater IPs mortality.

Accuracy of Helicobacter pylori diagnostic tests in patients with bleeding peptic ulcer: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and a meta-analysis of diagnostic accuracy of the different tests aimed to detect Helicobacter pylori infection in patients with upper gastrointestinal bleeding (UGIB).

SELECTION OF STUDIES

assessing the accuracy of H. pylori diagnostic methods in patients with UGIB.

SEARCH STRATEGY

electronic bibliographical searches.

DATA EXTRACTION

independently done by two reviewers.

DATA SYNTHESIS

meta-analyses of the different tests were performed combining the sensitivities, specificities, and likelihood ratios (LRs) of the individual studies.

RESULTS

Studies showed a high degree of heterogeneity. Pooled sensitivity, specificity, LR+ and LR- (95% confidence interval (CI)) for the different methods were: Rapid urease test (16 studies/1,417 patients): 0.67 (0.64-0.70), 0.93 (0.90-0.96), 9.6 (5.1-18.1), and 0.31 (0.22-0.44). Histology (10 studies/827 patients): 0.70 (0.66-0.74), 0.90 (0.85-0.94), 6.7 (2.5-18.4), and 0.23 (0.12-0.46). Culture (3 studies/314 patients): 0.45 (0.39-0.51), 0.98 (0.92-1.00), 19.6 (4-96), and 0.31 (0.05-1.9). Urea breath test (8 studies/520 patients): 0.93 (0.90-0.95), 0.92 (0.87-0.96), 9.5 (3.9-23.3), and 0.11 (0.07-0.16). Stool antigen test (6 studies/377 patients): 0.87 (0.82-0.91), 0.70 (0.62-0.78), 2.3 (1.4-4), and 0.2 (0.13-0.3). Serology (9 studies/803 patients): 0.88 (0.85-0.90), 0.69 (0.62-0.75), 2.5 (1.6-4.1), and 0.25 (0.19-0.33).

CONCLUSION

Biopsy-based methods, such as rapid urease test, histology, and culture, have a low sensitivity, but a high specificity, in patients with UGIB. The accuracy of 13C-urea breath test remains very high in these patients. Stool antigen test is less accurate in UGIB. Although serology seems not to be influenced by UGIB, it cannot be recommended as the first diagnostic test for H. pylori infection in this setting.

Stool antigen test for the diagnosis of Helicobacter pylori infection: a systematic review

Our aim was to review systematically the diagnostic accuracy of the Helicobacter pylori stool antigen test. Bibliographical searches were performed in several electronic databases and abstracts from congresses up to May 2003. Eighty-nine studies (10,858 patients) evaluated the stool antigen test in untreated patients. Mean sensitivity, specificity, positive predictive value and negative predictive value were 91%, 93%, 92% and 87%, respectively. Analysis of the eight studies (1399 patients) in which pretreatment evaluation of the monoclonal stool antigen test was performed showed better (p < .001) results (96%, 97%, 96% and 97%, respectively), with a clearer distinction between positive and negative results. Thirty-nine studies (3147 patients) evaluated the stool antigen test for the confirmation of H. pylori eradication 4-8 weeks after therapy, with accuracies of 86%, 92%, 76% and 93% for mean sensitivity, specificity, positive predictive value and negative predictive value, respectively. Results were similar when a gold standard based on at least two methods was used. Relatively low accuracy was reported in some posttreatment studies with the polyclonal stool antigen test. However, excellent results (p < .001) were achieved in all the six studies evaluating the monoclonal stool antigen test 4-8 weeks posttreatment. Results evaluating the stool antigen test < 4 weeks posttreatment are contradictory. Proton-pump inhibitors seem to affect the accuracy of the stool antigen test. Sensitivity and/or specificity in patients with gastrointestinal bleeding may be suboptimal. The stool antigen test performs well in children. Finally, the stool antigen test seems to be a cost-effective method.

Antigen stool test for assessment of Helicobacter pylori infection in patients with upper gastrointestinal bleeding

BACKGROUND

Re-bleeding of Helicobacter pylori-associated peptic ulcer disease is reduced by H. pylori eradication.

AIM

To validate a non-invasive test, the Premium Platinum HpSA stool test, in patients with upper gastrointestinal bleeding.

METHODS

Stool samples of consecutive patients with relevant bleeding from gastric or duodenal ulcers or erosions were collected at initial endoscopy and during the following week. Samples were assessed using the HpSA test. H. pylori status was defined by three biopsy-based reference methods: culture, rapid urease test and histology. It was positive if culture was positive or if rapid urease test and histology were positive.

RESULTS

One hundred and fourteen patients (mean age, 66 years) were included. In accordance with the definition, 56 (49%) were H. pylori positive. The sensitivity and specificity of the first stool sample were 84% and 90%, respectively. The respective values for two samples from consecutive days were 91% and 86%. In comparison with a serum immunoglobulin G antibody enzyme-linked immunoabsorbent assay, the HpSA test showed superior specificity.

CONCLUSIONS

The diagnostic accuracy, in particular the sensitivity, of the HpSA stool test is reduced by upper gastrointestinal bleeding. The positive predictive value of 89%, however, justifies the initiation of eradication therapy on the basis of a positive stool test. A negative test result should be confirmed by a further diagnostic method.

Etiología de la hemorragia digestiva alta de origen péptico: papel de Helicobacter pylori y los antiinflamatorios no esteroideos

INTRODUCTION

Upper gastrointestinal bleeding continues to be a severe and frequent complication in ulcerative disease. Etiologic diagnosis in these patients is highly important in order to initiate appropriate treatment and prevent bleeding recurrence.

OBJECTIVE

1. To investigate the prevalence of Helicobacter pylori infection and use of NSAIDs in patients with upper gastrointestinal hemorrhage of peptic origin. 2. To analyze the strategy used for the diagnosis of H. pylori in our previous work. PATIENTS AND MEHTODS: Seventy-three patients with endoscopically-diagnosed upper gastrointestinal bleeding of peptic origin were included in the study. The use of NSAIDs was investigated. H. pylori infection was diagnosed if one of the following tests was positive: urease test, histology, breath test.

RESULTS

H. pylori infection was found in 92% of duodenal ulcers and in 88% of gastric ulcers. Fifty-six percent of the patients had taken NSAIDs. Excluding these patients resulted in an H. pylori infection rate of 96.7%. The diagnosis was based on urease test in 46%. In the remaining patients, breath test and histology were required.

CONCLUSIONS

The main etiology in patients with upper gastrointestinal bleeding of peptic origin is H. pylori infection followed by the use of NSAIDs, and these two factors frequently coexist. The strategy of performing a urease test and, when this is negative, performing histological study and a breath test, is valid and allows a diagnosis of H. pylori infection to be made even if patients are receiving treatment that could make diagnosis difficult.

Evaluación de un test rápido (ImmunoCard STAT! HpSA) para la detección de Helicobacter pylori en heces

INTRODUCTION

The use of a rapid diagnostic technique may be extremely useful for the management of Helicobacter pylori infection. A new immunochromatographic in-office test (ImmunoCard STAT! HpSA, Meridian Diagnosis Inc, Cincinnati, Ohio, USA) for the detection of H. pylori in feces has recently become available. The aim of the present study was to evaluate the diagnostic reliability and reproducibility of the ImmunoCard STAT! HpSA test in patients with dyspepsia.

PATIENTS AND METHODS

Sixty-three dyspeptic patients were enrolled. H. pylori status was determined by CLO-test and Giemsa staining of antral biopsy. Patients with a positive result for both tests were considered infected and those with a negative result for both tests were considered not infected. Fecal H. pylori antigen was tested twice by ImmunoCard STAT! HpSA. The sensitivity, specificity, positive predictive value and negative predictive value of each determination were calculated. The concordance between the two determinations was evaluated using Kappa statistics.

RESULTS

Of the 63 patients, 46 were infected by H. pylori. Sensitivity, specificity and positive and negative predictive values were 89-91%, 86-93%, 96-98% and 72-75%, respectively. The correlation coefficient between determinations was 0.845.

CONCLUSION

The new ImmunoCard STAT! HpSA test shows good sensitivity and reproducibility. Therefore, it could be highly useful in the management of H. pylori infection.

A new semiquantitative method of quantifying Helicobacter pylori in antigen stools

Stool antigen test for Helicobacter pylori, a noninvasive assay, is emerging as a strong competitor to urea breath test (UBT). Nevertheless, although the UBT delta value is a semiquantitative indicator of H. pylori intragastric load, until now the H. pylori stool antigen test has been used only as a qualitative investigation. We report here the results of a study performed with the aim of obtaining a semiquantitative measurement of bacterial amount in stools. We studied 15 patients with dyspepsia using H. pylori positivity at histology, the rapid urease test, UBT, and the H. pylori stool antigen test. The result of this last test was expressed by a numerical value we obtained by applying the principle of "standard points" to the absorbance units at spectrophotometric reading. This measurement was previously validated by testing probe sampling of H. pylori stool antigen with known pure and stool-mixed bacterial amounts. A numerical result for H. pylori stool antigen was correlated to UBT delta for each patient using Pearson's r test. Finally, a Student t test was performed to investigate possible differences in UBT and H. pylori stool antigen test values between anti-CagA-positive and -negative patients. We obtained a curve of saturation with both known amount of pure and stool-mixed bacteria. Pearson's r test showed a significant correlation between UBT delta value and H. pylori stool antigen measurement (r = 0.77; p < 0.001). Urea breath test delta and H. pylori stool antigen test values were significantly higher in anti-CagA-positive patients. Our data suggest that a numerical estimation of H. pylori stool antigen may be feasible. This evaluation, similarly to UBT delta, may represent a semiquantitative determination of bacterial intragastric load.