José María Pajares

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.

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.

Proton pump inhibitor, clarithromycin and either amoxycillin or nitroimidazole: a meta-analysis of eradication of Helicobacter pylori

To perform a meta‐analysis of studies comparing twice daily, one‐week triple therapy with a proton pump inhibitor, clarithromycin (C) and amoxycillin (A) (PCA) vs. those using proton pump inhibitor, clarithromycin and a nitroimidazole (N) (PCN) for H. pylori eradication.

Proton pump inhibitors versus H2‐antagonists: a meta‐analysis of their efficacy in treating bleeding peptic ulcer

To evaluate whether proton pump inhibitors are more effective than H2‐antagonists (H2‐A) for the treatment of bleeding peptic ulcer.

Prevalence of hepatitis C virus infection in porphyria cutanea tarda: systematic review and meta-analysis

BACKGROUND/AIMS To conduct a systematic review and meta-analysis on the prevalence of hepatitis C virus (HCV) infection in porphyria cutanea tarda (PCT). METHODS Studies evaluating prevalence of HCV infection in patients with PCT were considered. Bibliographical searches were conducted in several electronic databases. Studies comparing HCV prevalence in PCT (cases) and in a reference group (controls) were included in the meta-analysis, combining the Odds Ratios (OR) of the individual studies. RESULTS Fifty studies including 2,167 patients were identified. Mean HCV prevalence by serology was 47%, and 50% with polymerase chain reaction (PCR). HCV prevalence markedly varied depending on the country and the type of PCT (57% in the sporadic and 26% in the familial form). Eight case-control studies were identified. Seven studies compared HCV prevalence in PCT vs. healthy controls: 40% vs. 0.24%, respectively (OR=275; 95% confidence interval=104-725). Heterogeneity disappeared when only studies evaluating HCV infection by PCR were included. CONCLUSIONS HCV prevalence in patients with PCT is approximately 50%, much higher than that reported in general population, suggesting a possible etiopathogenic role of HCV in PCT. The striking geographical variation in this association suggests that genetic and/or environmental factors may also be involved in the pathogenesis of this disorder.

Diagnosis of Helicobacter pylori infection by stool antigen determination: a systematic review

Recently a new, noninvasive diagnostic test based on the detection of Helicobacter pylori stool antigen (SA) has been developed. The aim of this study was to systematically review the experience on H. pylori SA test for the diagnosis of H. pylori infection. Bibliographic searches were performed in the PubMed database and abstracts from several congresses. A total of 43 studies fulfilled the inclusion criteria and evaluated H. pylori SA test accuracy for the diagnosis of H. pylori infection in nontreated patients. Overall, 4769 patients were included. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) (weighted mean) were, respectively: 92.4% (95% CI = 91–93%), 91.9% (91–92%), 92.1% (91–93%), and 90.5% (90–91%). Therefore the SA test can definitively be considered an accurate noninvasive method for the diagnosis of H. pylori infection in untreated patients. A total of 25 studies including 2078 patients evaluated H. pylori SA test for the confirmation of H. pylori eradication ≥4 wk after completion of therapy. Sensitivity, specificity, PPV and NPV (weighted mean) were: 88.3% (87–90%), 92% (91–93%), 75.1% (73–77%), and 94.8% (94–96%). Although most studies showed that SA test is an accurate method to confirm H. pylori eradication ≥4 wk after treatment, these favorable results were not confirmed in other studies. Further investigation is necessary to explain these discrepancies, as well as to clarify the precise time for confirmation of eradication after therapy, the appropriate cutoff point for the SA test, and which factors influence it. Proton pump inhibitors seem to affect the accuracy of SA test, but the negative effect disappears 1–2 wk after stopping treatment. The SA test is technically feasible in patients with upper GI bleeding, although the true diagnostic accuracy in this group of patients remains to be more fully assessed. Finally, the SA test seems to be a highly cost-effective method for the diagnosis of H. pylori infection.

‘Rescue’ Therapy with Rifabutin after Multiple Helicobacter pylori Treatment Failures

Aim. Eradication therapy with proton pump inhibitor, clarithromycin and amoxicillin is extensively used, although it fails in a considerable number of cases. A ‘rescue’ therapy with a quadruple combination of omeprazole, bismuth, tetracycline and metronidazole (or ranitidine bismuth citrate with these same antibiotics) has been recommended, but it still fails in approximately 20% of cases. Our aim was to evaluate the efficacy and tolerability of a rifabutin‐based regimen in patients with two consecutive H. pylori eradication failures.

Systematic review: regression of lymphoproliferative disorders after treatment for hepatitis C infection

Aim:  To systematically review the experience of therapeutic studies where α‐interferon with or without ribavirin was administered to patients with lymphoproliferative disorders, in order to evaluate whether eradication of hepatitis C virus may induce regression of lymphoproliferative disorders.

Helicobacter pylori "rescue" therapy after failure of two eradication treatments.

Nowadays, apart from having to know well first‐line eradication regimens, we must also be prepared to face Helicobacter pylori treatment failures. Therefore, in designing a treatment strategy we should not focus on the results of primary therapy alone, but also on the final – overall – eradication rate. After failure of a combination of proton pump inhibitor (PPI), amoxicillin, and clarithromycin, the use of empirical quadruple therapy (PPI–bismuth–tetracycline–metronidazole), has been generally used as the optimal second‐line therapy. Even after two consecutive failures, several studies have demonstrated that H. pylori eradication can finally be achieved in almost all patients if several “rescue” therapies are consecutively given. It seems that performing culture even after a second eradication failure may not be necessary, as it is possible to construct an overall strategy to maximize H. pylori eradication, based on the different possibilities of empirical treatment (when antibiotic susceptibilities are unknown). Thus, if one does not want to perform culture before the administration of the third treatment after failure of the first two, different empirical treatments exist, including regimens based on: 1, amoxicillin (amoxicillin–PPI at high doses); 2, amoxicillin plus tetracycline (PPI–bismuth–tetracycline–amoxicillin, or ranitidine–bismuth–citrate–tetracyline–amoxicillin); 3, rifabutin (rifabutin–amoxicillin–PPI); 4, levofloxacin (levofloxacin–amoxicillin–PPI); and 5, furazolidone (furazolidone–bismuth–tetracycline–PPI).

Helicobacter pylori eradication therapy is more effective in peptic ulcer than in non-ulcer dyspepsia.

Aim To evaluate whether eradication therapy is more effective in peptic ulcer disease (PUD) than in non-ulcer dyspepsia (NUD). Methods We retrospectively studied 481 patients with NUD (183 patients) or PUD (298 patients) infected with Helicobacter pylori included in several prospective clinical trials. Three eradication regimens were given: (1) proton pump inhibitor (PPI) plus clarithromycin, plus either amoxycillin or metronidazole for 7 days (297 patients); (2) ranitidine bismuth citrate (RBC) plus clarithromycin plus amoxycillin for 7 days (79 patients); and (3) RBC plus clarithromycin plus amoxycillin plus metronidazole for 5 days (105 patients). H. pylori eradication was defined as a negative 13C-urea breath test 4 weeks after completing treatment. Results H. pylori eradication rates were 82% (95% CI 78–87%) with PPI plus two antibiotics for 7 days, 85% (95% CI 75–91%) with RBC plus two antibiotics for 7 days, and 91% (95% CI 86–97%) with RBC plus three antibiotics for 5 days (P < 0.05 compared with the first regimen). Overall, the H. pylori eradication rate in patients with NUD was 78% (95% CI 71–84%), while in patients with PUD it was 89% (95% CI 86–93%) (P < 0.001). Both the combination of PPI plus two antibiotics for 7 days and the combination of RBC plus three antibiotics for 5 days were more effective in PUD than in NUD patients. However, RBC plus clarithromycin plus amoxycillin for 7 days was equally effective in both diseases. RBC plus two antibiotics for 7 days achieved better results than the same therapy with PPI only in NUD patients (84%v. 59%, P < 0.01), but both regimens were similar when prescribed in PUD patients (86%v. 88%). In the multivariate analysis, the type of therapy, the diagnosis (NUD v. PUD), and the product variable of therapy (with RBC plus 2 antibiotics for 7 days) and diagnosis (interaction variable) were the only variables that influenced H. pylori eradication. The odds ratio (OR) for the effect of RBC versus PPI plus two antibiotics for 7 days in patients with NUD was 4 (95% CI 1.7–9.7;P < 0.01), whereas in patients with PUD no statistical significance was achieved (OR 0.79; 95% CI 0.2–3.9). Conclusion Overall, H. pylori eradication therapy is more effective in PUD than in NUD patients. This advantage of eradication therapies in PUD patients seems to be observed with 7-day PPI-based triple regimens, and with 5-day RBC-based quadruple therapy, while the 7-day RBC-based triple regimen seems to be equally effective in both diseases.