Validation of a symptom diary for patients with gastro-oesophageal reflux disease

BACKGROUND

Symptom diaries are potentially attractive but, because of concerns about patient compliance, they have had limited use in clinical trials. We assessed the validity and responsiveness of a symptom diary for patients with gastro-oesophageal reflux disease.

METHODS

We included 215 patients with gastro-oesophageal reflux disease after starting treatment for 4 weeks with 40 mg esomeprazole once daily. Patients recorded whether they experienced night-time heartburn (yes/no), the severity of daytime heartburn on a scale from 1 (no heartburn) to 4 (severe heartburn) and their antacid use. Patients also completed a number of disease-specific and preference-based Health-related Quality of Life questionnaires at baseline and follow-up.

RESULTS

Consistent with a priori predictions, daytime heartburn showed moderate to strong correlations with the Quality of Life in Reflux and Dyspepsia questionnaire (0.36-0.67) and four scales of symptom severity (0.36-0.70) for baseline, follow-up and change scores, but low correlations with the Standard Gamble. Responsiveness of the daytime heartburn item was excellent with a mean change from baseline to follow-up of -1.3 (95% CI -1.4 to -1.1) and a standardized response mean of 1.33 while responsiveness of the daily antacid use item was moderate (mean change scores -1.8 tablets taken, 95% CI -2.3 to -1.3 and standardized response mean of 0.64).

CONCLUSIONS

The excellent psychometric properties of this simple gastro-oesophageal reflux disease diary make it an attractive measure for future trials.

Do physicians correctly assess patient symptom severity in gastro-oesophageal reflux disease?

BACKGROUND

The accuracy of physicians' assessment of the severity of gastro-oesophageal reflux disease is unclear.

AIM

To correlate physician and patient assessment of gastro-oesophageal reflux disease severity and its response to treatment.

METHODS

Adult uninvestigated gastro-oesophageal reflux disease patients (n = 217) completed symptom and health-related quality of life questionnaires at baseline and after treatment with esomeprazole 40 mg p.o. daily. Pearson coefficients quantified correlations between physician assessments and patient responses.

RESULTS

At baseline, the strongest correlations were heartburn severity (0.31), overall symptom severity (0.44) and a domain of the quality of life in reflux and dyspepsia questionnaire (0.31) (P < 0.001). Correlations of change with treatment were greater than baseline correlations: heartburn (0.39), overall symptoms (0.50) and global rate of change -- stomach problems (0.72, all P < 0.001). The mean difference between the physicians' assessment of change and the patients' global rating of change was 0.20 (95% confidence intervals: 0.10-0.29) with physicians overestimating benefit.

CONCLUSIONS

Correlations were often significant, although weak to moderate and better with symptom severity than with health-related quality of life instruments as well as with change after therapy than at baseline. Increasing attention to health-related quality of life may help physicians better understand patients' experience. In clinical trials, treatment success should be assessed by the patient as well as the physician.

There is no difference in the disease severity of gastro-oesophageal reflux disease between patients infected and not infected with Helicobacter pylori

BACKGROUND

The role of Helicobacter pylori in gastro-oesophageal reflux disease (GERD) is controversial.

AIM

To compare the severity of GERD in infected vs. non-infected patients, as part of an ongoing randomized controlled trial that examines the impact of H. pylori eradication on GERD-related outcomes.

METHODS

Consecutive GERD patients underwent urea breath testing and completed validated GERD symptom severity, and quality of life questionnaires as well as, 24-h pH-metry. These parameters, as well as demographics and endoscopic findings were assessed in double-blinded fashion and compared between H. pylori-infected and non-infected subjects.

RESULTS

Helicobacter pylori-infected GERD patients (n=50) were significantly older and less educated than non-infected patients (n=51). They also used proton pump inhibitors less often but had no difference in symptoms (as measured with both the Spechler's Activity Index and the Gastrointestinal Symptom Rating Scale), quality of life, endoscopic findings or 24-h pH-metry findings.

CONCLUSION

This prospective, double-blind study demonstrates, using excellent GERD quantifying measures including validated symptom severity scores, endoscopy, and 24-h pH-metry, that there exist no clinically significant differences in clinical or laboratory-related GERD manifestations between H. pylori-infected and non-infected GERD patients.

The cost-effectiveness of high-dose oral proton pump inhibition after endoscopy in the acute treatment of peptic ulcer bleeding

BACKGROUND

Recent data suggest a role for high-dose oral proton pump inhibition in ulcer bleeding.

AIM

To compare the cost-effectiveness of oral high-dose proton pump inhibition to both high-dose intravenous proton pump inhibition and placebo administration.

METHODS

The model adopted a 30-day time horizon, and focused on patients with ulcer haemorrhage initially treated endoscopically for high-risk stigmata. Re-bleeding rates were set a priori based on non-head-to-head data from the literature, and charges and lengths of stay from a national American database. Sensitivity analyses were carried across a broad range of clinically relevant assumptions.

RESULTS

Re-bleeding rates for patients receiving intravenous, oral, or placebo therapies were 5.9%, 11.8%, and 27%, respectively. The mean lengths of stay and costs for admitted patients with and without re-bleeding were 4.7 and 3 days; $11,802, and $7993, respectively. High-dose intravenous proton pump inhibition was more effective and less costly (dominant) than high-dose oral proton pump inhibition with incremental savings of $136.40 per patient treated. The oral high-dose strategy in turn dominated placebo administration. Results remained robust according to one- and two-way sensitivity analyses.

CONCLUSION

In patients undergoing endoscopic haemostasis, subsequent high-dose intravenous proton pump inhibition is more cost-effective than high-dose oral proton pump inhibition, which in turn dominates placebo. The results from this exploratory-type cost analysis require confirmation by head-to-head prospective trials performed in Western populations.

Multilaboratory comparison of proficiencies in susceptibility testing of Helicobacter pylori and correlation between agar dilution and E test methods

Susceptibility testing was performed at seven Canadian microbiology laboratories and the Helicobacter Reference Laboratory, Halifax, Nova Scotia, Canada, to assess susceptibility testing proficiency and the reproducibility of the results for clarithromycin and metronidazole and to compare the Epsilometer test (E test) method to the agar dilution reference method. Control strain Helicobacter pylori ATCC 43504 (American Type Culture Collection) and 13 clinical isolates (plus duplicates of four of these strains including ATCC 43504) were tested blindly. The National Committee for Clinical Laboratory Standards (NCCLS) guidelines for agar dilution testing were followed, and the same suspension of organisms was used for agar dilution and E test. Antimicrobials and E test strips were provided to the investigators. Methods were provided on a website (www.Helicobactercanada.org). Each center reported MICs within the stated range for strain ATCC 43504. Compared to the average MICs, interlaboratory agreements within 2 log(2) dilutions were 90% (range, 69 to 100%) for clarithromycin by agar dilution, with seven very major errors [VMEs], and 85% (range, 65 to 100%) by E test, with three VMEs. Interlaboratory agreements within 2 log(2) dilutions were 83% (range, 50 to 100%) for metronidazole by agar dilution, with six VMEs and eight major errors (MEs), and 75% (range, 50 to 94%) by E test, with four VMEs and four MEs. At lower and higher concentrations of antibiotic, E test MICs were slightly different from agar dilution MICs, but these differences did not result in errors. When a standardized protocol based on NCCLS guidelines was used, most participants in this study correctly identified clarithromycin- and metronidazole-susceptible and -resistant strains of H. pylori 93% of the time by either the agar dilution or E test method, and the numbers of errors were relatively equivalent by both methods.

High-dose intravenous proton pump inhibition following endoscopic therapy in the acute management of patients with bleeding peptic ulcers in the USA and Canada: a cost-effectiveness analysis

BACKGROUND

The efficacy of high-dose intravenous proton pump inhibition has recently been shown, yet its cost-effectiveness remains poorly studied.

AIM

To assess the cost-effectiveness of this approach separately for American and Canadian health care settings.

METHODS

A validated decision model included patients with bleeding ulcers after successful endoscopic haemostasis. Probabilities were determined from the literature, and charges and lengths of stay from national databases. A third-party payer perspective was adopted over a 30-day time horizon.

RESULTS

Re-bleeding rates were 5.9% for patients who received high-dose intravenous proton pump inhibition and 22.9% for those who did not. Hospitalization costs for patients with and without re-bleeding were 11,802 US dollars and 7993 US dollars, and 5220 Canadian dollars and 2696 Canadian dollars, respectively. High-dose intravenous proton pump inhibition was more effective and less costly than the alternative of not administering it. The cost-effectiveness ratios for high-dose and no high-dose intravenous proton pump inhibition were 9112 US dollars and 11,819 US dollars (3293 dollars and 4284 dollars for the Canadian case), respectively. Sensitivity and threshold analyses showed that the results were robust across a wide range of clinically relevant assumptions.

CONCLUSION

In the USA and Canada, administering high-dose intravenous proton pump inhibition for 3 days is both more effective and less costly than not doing so for patients with bleeding ulcers after successful endoscopic haemostasis.

Treatment of Helicobacter pylori infection

It has been 2 decades since the rediscovery of Helicobacter pylori. Since that time, enormous advances have occurred: H. pylori is clearly felt to be a cause of peptic ulcer disease and gastric malignancies such as mucosa associated lymphoid tissue (MALT) lymphoma and a carcinogenic factor for gastric adenocarcinoma. These associations have led to clear indications for H. pylori treatment in certain conditions, but in other diseases where the associations are not as clear, the indications also remain relatively controversial. Clear indications for H. pylori treatment include patients with duodenal and gastric H. pylori associated ulcers and MALT lymphoma. In uninvestigated dyspepsia, there are also very clear benefits to H. pylori treatment whereas in non-ulcer dyspepsia, the benefits are controversial. H. pylori is certainly a risk factor for gastric adenocarcinoma but eradication of this infection has not yet been shown to reduce or eliminate the risk of developing this condition. The effect of H. pylori treatment in patients with gastroesophageal reflux disease is also unclear. There is a potential benefit in the prevention of atrophic gastritis but a potential disadvantage is the worsening of reflux disease, which has been suggested by certain studies. In addition, the interaction between H. pylori and nonsteroidal anti-inflammatory drugs (NSAIDs) appears quite complicated. Although there have been several advances in the last 2 decades with regards to the treatment of H. pylori, several controversies still exist, attesting to the requirement for further research.

Helicobacter DNA in bile: correlation with hepato-biliary diseases

BACKGROUND

Helicobacter has been identified in isolated cases of hepato-biliary diseases, but its role in the pathogenesis of these conditions remains unclear.

AIM

To determine whether Helicobacter could be detected in bile obtained at endoscopic retrograde cholangiopancreatography, and to evaluate the prevalence of this infection in patients with hepato-biliary diseases.

METHODS

Bile was collected from 125 patients with various hepato-biliary diseases undergoing endoscopic retrograde cholangiopancreatography. Among them, 75 were diagnosed with biliary stones, 15 with pancreatico-biliary malignancies and four with primary sclerosing cholangitis. The detection of Helicobacter in DNA extracted from these bile samples was performed using Helicobacter genus-specific primers (capable of detecting 100-1000 organisms/mL).

RESULTS

Helicobacter was detected in all positive controls. Only three samples had polymerase chain reaction inhibitors. All remaining bile samples (122 patients with hepato-biliary diseases) were negative for Helicobacter DNA.

CONCLUSIONS

Helicobacter can be detected in bile samples using polymerase chain reaction. This infection, however, was not present in any of our patients diagnosed with gallstones or hepato-biliary malignancies, raising doubt as to the possible association between Helicobacter and these entities. Given the low sample size of patients with primary sclerosing cholangitis, more studies are required to determine whether an association exists with this condition.

Efficacy and safety of single-triple capsules of bismuth biskalcitrate, metronidazole and tetracycline, given with omeprazole, for the eradication of Helicobacter pylori: an international multicentre study

BACKGROUND

The high prevalence of Helicobacter pylori resistance to metronidazole demands treatments more effective than standard bismuth-based triple therapy against these strains.

AIM

To evaluate the H. pylori eradication rate in both metronidazole-sensitive and -resistant strains following quadruple therapy using single-triple capsules of bismuth biskalcitrate, metronidazole and tetracycline, given with omeprazole.

METHODS

One hundred and seventy valid patients with duodenal ulcer, gastric ulcer or non-ulcer dyspepsia were treated in eight centres located in five countries. H. pylori was confirmed at baseline using 13C-urea breath test, histology and/or culture. Patients received three single-triple capsules q.i.d. and omeprazole, 20 mg b.d., for 10 days. Each capsule contained bismuth biskalcitrate, 140 mg (as 40 mg Bi2O3 equivalent), metronidazole, 125 mg, and tetracycline, 125 mg. 13C-Urea breath test was repeated at least 4 and 8 weeks post-treatment.

RESULTS

Overall eradication rates were 93% (158/170) by modified intention-to-treat analysis and 97% (142/146) by per protocol analysis. Eradication rates were 93% (40/43) and 95% (38/40) for strains resistant to metronidazole and 95% (82/86) and 99% (75/76) for strains sensitive to metronidazole by modified intention-to-treat and per protocol analysis, respectively.

CONCLUSION

This omeprazole-bismuth biskalcitrate-metronidazole-tetracycline 10-day regimen is a very effective and well-tolerated treatment, which overcomes metronidazole resistance.

Gastroesophageal reflux and hyperacidity in chronic renal failure

The prevalence of H. pylori infection and PUD seem not to be different in CRF patients as compared with the general population. However, PUD in CRF patients seems to have some unique features-namely, lack of pain and higher associations with bleeding, with post-bulbar location, and with multiple ulcers. No increase in GERD has been proven in adults, but several studies demonstrate increased GERD in pediatric CRF patients. The causes of the increase in GERD may include delayed gastric emptying owing to altered myoelectric activity, or perhaps to an increased production of gastric acid, but evidence for the latter is small. Importantly, treating the problem may lead to better nutrition and higher albumin levels, thus improving patient prognosis.

Bismuth-based quadruple therapy with bismuth subcitrate, metronidazole, tetracycline and omeprazole in the eradication of Helicobacter pylori

BACKGROUND

A previous study showed that 14 days of qid bismuth-based triple therapy with tetracycline 500 mg, metronidazole 250 mg and colloidal bismuth subcitrate 120 mg resulted in excellent Helicobacter pylori eradication rates (89.5%). The present study looked at a shorter treatment period by adding omeprazole and by reducing the dose of tetracycline.

METHODS

One hundred sixty-one patients with H pylori confirmed by histology and (13)carbon urea breath test were included in the study. They were treated for seven days with bismuth subcitrate 120 mg plus metronidazole 250 mg plus tetracycline 250 mg qid plus omeprazole 20 mg bid (OBMT). Patients were 18 to 75 years of age and had dyspepsia with or without a history of peptic ulcer. Patients with irritable bowel syndrome, active ulcer or previous attempt at eradication, or those who had used antibiotics or antiulcer drugs in the previous 30 days were excluded. Eradication was determined by two (13)carbon urea breath tests done one and three months, respectively, after treatment. Strains with minimal inhibitory concentrations of 8 microg/mL or higher were considered to be resistant to metronidazole.

RESULTS

The overall per protocol eradication rate was 84%-89.5% in metronidazole-sensitive and 70.8% in metronidazole-resistant strains. Modified intent-to-treat analysis resulted in a 80% eradication rate--82.5% in metronidazole-sensitive and 66.7% in metronidazole-resistant strains. Only one patient discontinued treatment because of adverse events.

CONCLUSIONS

The OBMT regimen used in this study is safe and effective against metronidazole-sensitive H pylori strains.

Implications of antibiotic resistance in the management of Helicobacter pylori infection: Canadian Helicobacter Study Group

Eradication of Helicobacter pylori from the gastric and duodenal mucosa is an important clinical goal in the treatment of infected patients with peptic ulcer disease and other H pylori-associated conditions. Although several oral drug combination regimens are associated with eradication rates of approximately 85% in controlled trials, the success rate in patients infected with a resistant strain of H pylori is closer to 75%. Resistance to metronidazole and clarithromycin, which are common components of combination treatment regimens, is of greatest concern. Reported rates of H pylori resistance to various antibiotics vary considerably. In Canada, the data documenting H pylori susceptibility are limited but suggest that resistance to these antibiotics varies geographically and within specific treatment groups. Although susceptibility testing is not a prerequisite for initial treatment of individual patients infected with H pylori, formal efforts to identify and monitor both the causes and prevalence of antibiotic resistance across Canada are a much needed step in the ongoing management of this important infection. Recommended treatment regimens may be useful, even for treating apparently resistant H pylori strains. However, it is important to understand the mechanisms of the development of resistant strains to manage patients with treatment failure better.

Epidemiology of the antibiotic resistance of Helicobacter pylori in Canada

BACKGROUND

The rate of Helicobacter pylori resistance to antibiotics determines the cure rate of treatment regimens containing such antibiotics.

AIMS

To review the literature to determine the rates of H pylori resistance to metronidazole and clarithromycin in Canada, and whether these rates vary in different regions of Canada.

METHODS

The literature was reviewed extensively for the prevalence of antibiotic-resistant H pylori in Canada by searching MEDLINE from January 1980 to May 1999, as well as abstracts of the American Gastroenterology Association Digestive Disease Week, Canadian Digestive Disease Week and The European H pylori Study Group Meetings from January 1995 to May 1999.

RESULTS

Eleven studies that estimated H pylori resistance to metronidazole resistance and nine that estimated resistance to clarithromycin in Canada were identified. Rates of resistance for metronidazole and clarithromycin varied from 11% to 48% and 0% to 12%, respectively. Studies that obtained their estimates using the E-test and those that did not clearly exclude patients who had undergone previous attempts at H pylori eradication had higher estimates of resistance, accounting for this variability in results.

CONCLUSIONS

The prevalence of primary H pylori resistance in Canada appears to be 18% to 22% for metronidazole and less than 4% for clarithromycin. These rates appear to be consistent across the different regions studied in Canada, but many regions have not been studied.

Genetic variability determinants of Helicobacter pylori: influence of clinical background and geographic origin of isolates

Helicobacter pylori has an unusual pattern of genetic variation, which complicates research on this organism. To gain a better understanding of the forces behind this phenomenon, the extent to which recombination and single point mutations affect genetic variability in H. pylori was quantified and the influence of both geographical distance and clinical background were assessed. Site-directed restriction-endonuclease digestion of 2 gene fragments was performed on 168 isolates from Montreal and Berlin. Allelic diversity was found to be much higher for H. pylori than for other bacterial species. This finding is consistent with those of previous studies on H. pylori that were conducted using other techniques. However, nucleotide diversity was within the range reported for other bacterial species. Phylogenetic analysis found no grouping of strains with clinical background or geographical origin. Recombination at a rate that resulted in linkage equilibrium within genes can explain these observations.

Is Helicobacter pylori eradication associated with gastroesophageal reflux disease?

OBJECTIVES

A recent report has suggested an association between Helicobacter pylori eradication and the development of gastroesophageal reflux disease (GERD). We therefore assessed the incidence of GERD among comparable patients having undergone successful versus failed H. pylori eradication in a controlled trial. We also compared the H. pylori strains in the subjects that developed GERD to those that did not.

METHODS

Patients with a history of proven duodenal ulcer and H. pylori infection were randomised into a H. pylori eradication study. Patients subsequently underwent gastroscopy with gastric biopsies every 3 months for 1 yr. At each visit, the presence of GERD symptoms and endoscopic esophagitis were noted, and the incidence of these variables among patients in whom H. pylori eradication was successful was compared to those in whom it was not. In a subgroup, the presence of the cagA, cagE, and vacA genotypes and of cagA antibodies were determined.

RESULTS

Of 98 patients randomized into this study, 11 dropped out before determination of H. pylori eradication, leaving 87 patients with analyzable results. H. pylori eradication was successful in 63 (72%). By the end of the follow-up period, patients with GERD symptoms or endoscopic esophagitis were more prevalent in the successful than in the failed eradication group (37% [95% CI: 25-50%] vs 13% [95% CI: 3-32%], p = 0.04, 95% CI for the difference: 6-42%), as were patients with GERD symptoms alone (29% [95% CI: 18-41%] vs 8% [95% CI: 1-27%], p = 0.04, 95% CI for the difference: 4-36%) or esophagitis alone (21% [95% CI: 12-33%] vs 4% [95% CI: 0-21%], p = 0.10, 95% CI for the difference: 4-29%, respectively). Multivariate analysis revealed no significant association between the incidence of symptoms or esophagitis and age, gender, Quetelet index, caffeine or alcohol intake, smoking, weight change, or the presence of a hiatus hernia. There were also no differences in the prevalence of H. pylori genotypes from patients who developed GERD as compared to those who did not.

CONCLUSIONS

In this patient population, the incidence of new GERD-type symptoms or endoscopic esophagitis was greater in patients in whom successful eradication was achieved. This difference does not appear to be attributable to weight gain, habits, or specific H. pylori strains.

Is Helicobacter pylori eradication associated with gastroesophageal reflux disease?

OBJECTIVES

A recent report has suggested an association between Helicobacter pylori eradication and the development of gastroesophageal reflux disease (GERD). We therefore assessed the incidence of GERD among comparable patients having undergone successful versus failed H. pylori eradication in a controlled trial. We also compared the H. pylori strains in the subjects that developed GERD to those that did not.

METHODS

Patients with a history of proven duodenal ulcer and H. pylori infection were randomised into a H. pylori eradication study. Patients subsequently underwent gastroscopy with gastric biopsies every 3 months for 1 yr. At each visit, the presence of GERD symptoms and endoscopic esophagitis were noted, and the incidence of these variables among patients in whom H. pylori eradication was successful was compared to those in whom it was not. In a subgroup, the presence of the cagA, cagE, and vacA genotypes and of cagA antibodies were determined.

RESULTS

Of 98 patients randomized into this study, 11 dropped out before determination of H. pylori eradication, leaving 87 patients with analyzable results. H. pylori eradication was successful in 63 (72%). By the end of the follow-up period, patients with GERD symptoms or endoscopic esophagitis were more prevalent in the successful than in the failed eradication group (37% [95% CI: 25-50%] vs 13% [95% CI: 3-32%], p = 0.04, 95% CI for the difference: 6-42%), as were patients with GERD symptoms alone (29% [95% CI: 18-41%] vs 8% [95% CI: 1-27%], p = 0.04, 95% CI for the difference: 4-36%) or esophagitis alone (21% [95% CI: 12-33%] vs 4% [95% CI: 0-21%], p = 0.10, 95% CI for the difference: 4-29%, respectively). Multivariate analysis revealed no significant association between the incidence of symptoms or esophagitis and age, gender, Quetelet index, caffeine or alcohol intake, smoking, weight change, or the presence of a hiatus hernia. There were also no differences in the prevalence of H. pylori genotypes from patients who developed GERD as compared to those who did not.

CONCLUSIONS

In this patient population, the incidence of new GERD-type symptoms or endoscopic esophagitis was greater in patients in whom successful eradication was achieved. This difference does not appear to be attributable to weight gain, habits, or specific H. pylori strains.

cagE is a virulence factor associated with Helicobacter pylori-induced duodenal ulceration in children

This study was undertaken to determine whether infection with Helicobacter pylori strains that contain the cagE gene was associated with duodenal ulceration in children. The presence of flaA, cagA, and cagE genes was determined by polymerase chain reaction in H. pylori previously cultured from 29 children. Twelve (92%) of 13 children with duodenal ulcers were infected with cagE-positive isolates, compared with only 5 (31%) of 16 with gastritis alone (P<.01). Infection of gastric cells in tissue culture by cagE-positive H. pylori resulted in greater increments in interleukin-8 levels compared with cagE-negative strains (2.3+/-0.1 vs. 1.3+/-0.2 ng/mL in AGS cells [P<.005]; 1.5+/-0.3 vs. 0.5+/-0.2 ng/mL in KATO-III cells [P<.05]). H. pylori-containing cagE was associated with the presence of duodenal ulceration in children. Enhanced chemokine production after infection with cagE-positive H. pylori could affect disease outcome.

Association of Helicobacter pylori genotype with gastroesophageal reflux disease and other upper gastrointestinal diseases

OBJECTIVE

Helicobacter pylori (H. pylori) is a recognized pathogen, but it may also have a protective effect for gastroesophageal reflux disease (GERD). We compared the prevalence of potential virulence factors (cagA, cagE, vacA genotypes) in GERD to other upper gastrointestinal diseases and controls.

METHODS

A total of 405 patients underwent gastroscopy with H. pylori isolation and serum testing. Patient diagnostic subgroups were prospectively defined. Genotypes were determined by amplification using polymerase chain reaction. CagA antibodies were determined by western blot, enzyme-linked immunosorbent, and flow microsphere immunofluorescent assays.

RESULTS

Patients were grouped as follows: nonulcer dyspepsia (26%), GERD (20%), gastric ulcer (17%), duodenal ulcer (12%), gastric cancer (6%), or controls (19%). The cagA gene was present in 94-97% of subjects in all categories, but the cagA antibody was less prevalent in nonulcer dyspepsia (69%, 95% CI: 48-86%, p = 0.02) and GERD (69%, CI: 39-91%, p < 0.05) than in those with gastroduodenal pathology including gastric ulcer, duodenal ulcer, and gastric cancer (92%, CI: 81-98%). The cagE gene and vacA S1 genotype were more frequent in patients with gastroduodenal pathology (p < 0.01). GERD was associated with a significantly lower rate of vacA S1 genotype than controls (29% (CI: 10-56%) versus 80% (CI: 59-93%), p < 0.01). The vacA S1 genotype was associated with the presence of cagA antibodies.

CONCLUSIONS

The cagE and vacA S1 genotypes are more prevalent in patients with peptic ulcer or gastric cancer, suggesting a potential function in virulence for these genes. However, the vacA S1 genotype was also more prevalent in controls than GERD, suggesting a potential protective effect against GERD.

Predictors of failure of Helicobacter pylori eradication and predictors of ulcer recurrence: a randomized controlled trial

OBJECTIVE

In light of evidence that Helicobacter pylori treatment fails 5% to 20% of the time, the objective of this study was to determine predictors of unsuccessful H. pylori eradication and of duodenal ulcer recurrence.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Gastroenterology services of 2 general hospitals in Montreal, Que.

PATIENTS

All patients (aged 16 to 90) with an endoscopically proven duodenal ulcer within the previous year and H. pylori infection detected on antral biopsy were asked to participate; 85 were included.

INTERVENTIONS

Patients were randomized in double-blind fashion to 1 of 2 eradication therapies, consisting of metronidazole, bismuth subcitrate and either amoxicillin or placebo. Endoscopy was performed at follow-up every 3 months for 12 months.

OUTCOME MEASURES

Demographic data, characteristics of patients and disease, previous history and family history of ulcer disease, compliance at day 10 and day 28 of therapy; in vitro metronidazole resistance of H. pylori; eradication of H. pylori (determined by endoscopic biopsy 3 months after therapy); and ulcer recurrence within 12 months after therapy.

RESULTS

Metronidazole resistance (odds ratio [OR] 0.11, 95% confidence interval [CI] 0.017 to 0.69) was the only independent predictor of eradication. Compliance (as defined in the study), density of organisms on culture, as well as several other factors examined, were not significant predictors. Treatment group, although a significant factor on univariate analysis, was not an independent predictor on multivariate analysis, as there were relatively good eradication rates (82% and 97% among compliant patients) in both groups. With regard to ulcer recurrence, 3 independent predictors were identified: failed H. pylori eradication (OR 86.5, 95% CI 4.2 to 1769), unemployment (OR 13.2, 95% CI 1.8 to 95) and a family history of ulcer disease (OR 12.2, 95% CI 1.2 to 128).

CONCLUSIONS

The best predictor of ulcer recurrence is failure of H. pylori eradication, which, in turn, depends on metronidazole resistance. Hence, treatments containing metronidazole should be avoided in populations with high rates of metronidazole resistance. A family history of ulcer disease and unemployment were also predictors of ulcer recurrence, which suggests a potential role for treatment of contacts.

Canadian Helicobacter Study Group Consensus Conference on the Approach to Helicobacter pylori Infection in Children and Adolescents

Gastric infection with Helicobacter pylori is common in both children and adults, but children are considerably less susceptible to peptic ulcers and other pathological sequelae. As a result, the risk to benefit ratio of diagnostic studies and therapeutic regimens for H pylori in adults are likely different from those in pediatric populations. These guidelines for the management of pediatric H pylori infection, developed by the Canadian Helicobacter Study Group, are designed to identify when the diagnosis and treatment of H pylori may improve patient care. Given the low prevalence of this infection in Canada, it is important to recognize that indiscriminate testing and treatment programs in children are not recommended, and indeed may threaten the optimal care of children. Diagnostic tests should be employed judiciously and be reserved for children who are most likely to derive measurable benefit, such as those likely to have peptic ulcer disease. At this time a test and treat strategy in children cannot be considered prudent, evidence based or cost effective. It is appropriate to limit diagnosis and treatment to children and adolescents in whom H pylori has been identified during endoscopic investigation.

Host determinants of Helicobacter pylori infection and its clinical outcome

Greater than one-half of the world's population harbors Helicobacter pylori. The majority of infected individuals, however, remain asymptomatic, with only 10% to 20% developing diseases, including peptic ulcer disease, gastric cancer, and gastric mucosa-associated lymphoid tissue lymphoma. This article reviews host factors that may predispose an individual to both the acquisition of H. pylori infection and subsequent clinical outcome. Individuals with specific blood group antigens and human leukocyte antigen genotypes may be more susceptible to H. pylori infection. Additional factors, such as the age of acquisition, the host immune response, the site of infection, acid secretion, and interactions with nonhost factors (including bacterial virulence factors and environmental influences) may play a role in determining clinical outcome. Further investigation is required to clarify the mechanisms by which these interactions occur and, more critically, to determine their relative importance. This knowledge will enable the identification of individuals at risk of developing clinical disease with H. pylori infection.

Determinants of ethnic or geographical differences in infectivity and transmissibility of Helicobacter pylori

The prevalence of Helicobacter pylori infection is variable in different countries. There are two distinct patterns of H pylori prevalence with respect to age depending on the geographical region studied. The first pattern is widespread infection early in childhood with elevated prevalence rates of close to 80% throughout adulthood, and the second is increasing prevalence with age. This variability in pattern suggests a difference in infectivity or transmissibility of H pylori infection. Potential determinants of these differences are reviewed including environmental, bacterial and host factors. The most important determinant is likely socioeconomic class, which affects living conditions and sanitation, thus altering exposure to the bacterium. Host factors also play a role, perhaps via host receptors for H pylori. Bacterial factors may also contribute, although compelling evidence is lacking.

Canadian Helicobacter pylori Consensus Conference update: infections in adults. Canadian Helicobacter Study Group

The first Canadian Helicobacter pylori Consensus Conference took place in April 1997. The initial recommendations of the conference were published in early 1998. An update meeting was held in June 1998, and the present paper updates and complements the earlier recommendations. Key changes included the following: the recommendation for testing and treating H pylori infection in patients with known peptic ulcer disease was extended to testing and treating patients with ulcer-like dyspepsia; it was decided that the urea breath test (not serology) should be used for routine diagnosis of H pylori infection unless endoscopy is indicated for another reason; and recommended therapies were a twice daily, seven-day regimen of a proton pump inhibitor (omeprazole 20 mg, lansoprazole 30 mg, pantoprazole 40 mg) or ranitidine bismuth citrate 400 mg, plus clarithromycin 500 mg and amoxicillin 1000 mg, or plus clarithromycin 500 or 250 mg and metronidazole 500 mg. The need was reiterated to have funding for readily accessible, accurate testing for H pylori infection with the urea breath test. It was strongly recommended that regional centres be established to monitor the prevalence of antibiotic-resistant H pylori infections. The initial consensus document referred to pediatric issues that were not addressed in this update but were the subject of a subsequent Canadian Helicobacter Study Group meeting, and will be published later in 1999.

Gastric cytoprotection is secondary to increased mucosal fluid secretion: a study of six cytoprotective agents in the rat

We tested the hypothesis that rapidly developing gastric cytoprotection produced by topical application of exogenous compounds is a result of increased gastric mucosal fluid secretion. Ex vivo gastric chambers were prepared in rats which were subsequently exposed topically to one of the prostaglandin (PG) E1 analogues misoprostol or rioprostil, PGE2, nicotine, N-ethylmaleimide (NEM), 0.25 M HCl, or to their respective vehicles. All agents were added to empty chambers to avoid complications resulting from dilution by gastric contents. Effects of these agents on intraluminal volume changes, blood flow, juxtamucosal pH, histology, and on the mucosal damage resulting from necrotizing agents were studied. All six agents were cytoprotective and each increased net secretion of fluid by the chambered mucosae. Gastric blood flow was not significantly increased by NEM, by 0.25 M HCl, or by nicotine compared to controls, and the juxtamucosal pH was not significantly increased by any of the three agents for which this was studied. Vacuole formation in surface epithelial cells and subepithelial edema were seen after exposure to some agents, but none of the agents led to formation of a thick barrier of exfoliated cells and mucus. Ablation of primary afferent nerves with capsaicin abolished both protection by 0.25 M HCl and the net increase in fluid secretion by the mucosae. Capsaicin ablation did not alter either the protection afforded by NEM or the increase in volume of secretion. We conclude that increased mucosal fluid secretion is the common factor present with all six cytoprotective agents and hence may be the predominant mechanism of cytoprotection against topically applied necrotizing agents.

Utility of serology in determining Helicobacter pylori eradication after therapy

OBJECTIVE

To determine the usefulness of four serological tests in confirming cure of H pylori infection before the previously reported six-month post-treatment delay.

PATIENTS AND METHODS

As part of a prospective, blinded, controlled trial, in which patients with duodenal ulcers were randomized to receive different combinations of antibiotics, serum samples were obtained in 89 patients before treatment, as well as on several occasions after treatment. Antibody titres were determined by ELISA with Bio-Rad immunoglobulin (Ig) A, Bio-Rad IgG, Pyloriset EIA-A for IgA and Pyloriset EIA-G for IgG. Eradication was confirmed with antral biopsy three months after therapy.

RESULTS

The percentage drop in titre following treatment was significantly larger for the group of patients who were treated successfully with all four kits. Optimal cut-offs for identifying successful therapy were determined, and accuracy improved as the interval between testing and therapy was prolonged. Six months after therapy, the IgG test from Bio-Rad achieved 100% sensitivity and 80% specificity, and that from Pyloriset achieved 88% sensitivity and 100% specificity. At three months, however, test performance was quite good, with 90% sensitivity and 80% specificity when using a Pyloriset IgA titre drop of 20% or greater to predict successful eradication.

CONCLUSION

Serology is a simple, easily available, noninvasive method that exhibits good positive predictive value in the confirmation of successful cure of H pylori infection three or six months after treatment.

A review of the possible bacterial determinants of clinical outcome in Helicobacter pylori infection

Helicobacter pylori is present in 40-60% of the population and approximately 10-20% of these infected individuals suffer from a H. pylori associated disease such as peptic ulcer disease or gastric cancer. This article reviews the potential bacterial determinants responsible for and markers predictive of both the acquisition of H. pylori infection and subsequent clinical outcome; i.e., asymptomatic infection or disease. The acquisition of H. pylori infection depends on exposure (hence the increased risk in lower socioeconomic groups and developing nations) to viable bacteria with at least a functional urease gene in a susceptible host. Once infection occurs, bacterial virulence factors, including the vacuolating cytotoxin, and genes of the cag pathogenicity island, as well as nonbacterial factors may determine disease outcome. Future research is being directed at discovering other bacterial virulence factors responsible for the different clinical outcomes of H. pylori infection. This will be greatly enhanced by the recent release of the complete genome sequence of H. pylori. The determination of the relative importance of each of these recognized and other as yet unrecognized factors responsible for disease outcome will assist in the appropriate targeting of patients in the treatment of H. pylori infection.

In-vitro susceptibility of Helicobacter pylori to ampicillin, clarithromycin, metronidazole and omeprazole

The in-vitro activities of omeprazole and three antimicrobial agents against 89 clinical isolates of Helicobacter pylori from a population with duodenal ulcer disease were determined by an agar dilution method. Resistance rates were 20% for metronidazole (MIC > 8 mg/L), 1% for clarithromycin (MIC > 2 mg/L) and zero for ampicillin (MIC > 8 mg/L). Omeprazole was relatively active against H. pylori in vitro (MIC < or = 8 mg/L).

Hematoxylin and eosin staining of gastric tissue for the detection of Helicobacter pylori

BACKGROUND

Gold standard methods of detection of Helicobacter pylori are expensive, difficult to perform, or not widely available. The purpose of this study was to assess hematoxylin and eosin staining of antral tissue, a relatively inexpensive and widely available method of H. pylori detection.

MATERIALS AND METHODS

The hematoxylin and eosin stain was assessed as a method of H. pylori detection, with 2 x 2 table analysis using culture as the gold standard in 133 gastric biopsy specimens obtained from patients both before and following attempted eradication.

RESULTS

Performance of the stain was good among untreated patients as well as among patients having previously undergone an eradication treatment, with an overall accuracy of 92% (95% confidence intervals: 86-96), sensitivity of 93% (87-97), and specificity of 87% (69-96).

CONCLUSION

The hematoxylin and eosin stain is an inexpensive method of H. pylori detection but with test performance characteristics inferior to Giemsa, Genta, or silver stains.

Detection of Helicobacter pylori infection by saliva IgG testing

OBJECTIVES

Most currently available tests for the detection of Helicobacter pylori are invasive, time consuming, or impractical. We examined the test performance of a simple and rapidly administered salivary IgG assay kit in the diagnosis of Helicobacter pylori infection.

METHODS

Patients referred to a tertiary care setting for upper gastrointestinal endoscopy were included in a prospective evaluation of the test performance of the Helisal Kit which uses an ELISA technique to determine IgG antibodies in saliva. The results of the salivary IgG assay were compared to those of the Helisal Serum Kit, and to gastric histology. Two by two contingency table analyses were performed, and 95% confidence intervals (CI) were determined.

RESULTS

Upper gastrointestinal endoscopy was performed on 106 patients over a 3-month period. A statistically significant correlation was found between the blood and saliva IgG results (r = 0.60, p = 0.0001). When compared to serum IgG, the salivary assay test performance was: sensitivity 84% (CI: 70-93%), specificity 81% (CI: 69-90%), positive predictive value 76% (CI: 61-87%), negative predictive value 88% (CI: 76-95%), and diagnostic accuracy 88% (CI: 76-95%). Compared with gastric histology, the test performance of the salivary IgG assay decreased to: sensitivity 66% (CI: 52-79%), specificity 74% (CI: 60-85%), positive predictive value 71% (CI: 57-83%), negative predictive value 68% (CI: 55-80%), and diagnostic accuracy 70% (CI: 60-78%). More specifically, the salivary assay gave false-negative results in nine of 17 patients with duodenal ulcers. Results did not vary significantly when outcomes of the salivary and serum assays were combined. The incremental information obtained in the salivary test was greatest in the patient population exhibiting an intermediate pretest probability (30-70%) of being infected with Helicobacter.

CONCLUSION

The salivary IgG results correlated significantly with the serum IgG titers but exhibited only modest test performance, compared with the results of gastric histology. This salivary test may be most useful in certain patient subpopulations or in specific clinical contexts.

Determination of the test performance of less costly methods of Helicobacter pylori detection

Since Helicobacter pylori (Hp) has become so important in the management of peptic ulcers, it is imperative that noninvasive and inexpensive methods of diagnosis be available. The objective of this prospective, double-blind study was to determine the performance of the noninvasive 14C-urea breath test and the less expensive hematoxylin-phloxin-saffron (HPS) and Giemsa stains in the detection of this infection. As well, we set out to determine the minimal number of biopsies required to make an accurate diagnosis. Fifty consenting adults referred for gastroscopy underwent antral biopsies for HPS, Giemsa and Steiner silver staining and a 14C-urea breath test. The ability of HPS, Giemsa, and the breath test to differentiate between the presence or absence of Hp infection as defined by the silver stain was assessed using contingency table analysis. Hp was detected in 24 patients with the silver stain. Half of these patients had evidence of ulcer disease, compared to 3 of 26 patients who were negative for Hp on silver stain (p < 0.01). The Hp positive group were more frequently male (62% vs. 31%, p < 0.05) and more often had chronic active gastritis (96% vs. 7.7%, p < 0.001). The sensitivity of the breath test, HPS, and Giemsa stains were 95.8% (95% confidence interval: 79-100%), 75% (53-90%), and 95.8% (79-100%), respectively. Specificity was 100% (87-100%) for all 3 methods of detection. The breath test was also able to discriminate between heavily infected and moderately infected patients as defined by silver stain (p < 0.05), and could be shortened from 30 to 15 min without any loss of accuracy.(ABSTRACT TRUNCATED AT 250 WORDS)

Topical nicotine protects rat gastric mucosa against ASA-induced damage. A role for mucosal fluid secretion in cytoprotection

Acute intragastric nicotine administration has previously been shown to protect against ethanol-induced gastric mucosal damage. The aim of this study was to examine the effects of acute nicotine exposure on ASA-induced gastric mucosal damage and to determine if nicotine's protective effect is secondary to an increase in mucosal blood flow or in mucosal fluid secretion, as reflected by changes in the juxtamucosal pH gradient and volume of intragastric fluid. Mucosal blood flow, using a laser Doppler flowmeter, juxtamucosal pH gradient (depth, magnitude, and surface pH), using antimony microelectrodes, and changes in volume of luminal bathing solutions were measured in rat ex vivo gastric chamber preparations prior to and after a 10-min exposure to topical nicotine (1 mg in 8 ml of 0.2 M mannitol in 50 mM HCl), or to mannitol-HCl solution (vehicle). This was followed by application of acidified ASA (80 mM in 160 mM HCl) to the chambered mucosae for 10 min. Lesion area, expressed as the percentage of total glandular mucosa which was damaged, was significantly (P < 0.05) reduced by nicotine pretreatment. Blood flow decreased with nicotine exposure by 18.4%, compared to 13.6% in the control group (NS). Both gradient depth and gastric fluid volume increased significantly in the nicotine group (P < 0.05) compared to controls. Yohimbine pretreatment prevented both the increase in juxtamucosal pH gradient depth and the protective effect of nicotine. These results suggest that acute intragastric nicotine exposure protects against ASA-induced gastric damage in rats.(ABSTRACT TRUNCATED AT 250 WORDS)