The Association and Clinical Implications of Gastroesophgeal Reflux Disease and H. pylori

Similar documents
Esophageal Adenocarcinoma Developing after Eradication of Helicobacter pylori

Safety Of. long-term PPI. Layli Eslami, MD Tehran, 1393

Disclosures. GI Motility Disorders. Gastrointestinal Motility Disorders & Irritable Bowel Syndrome

Frequency of Barrett Esophagus in Patients with Symptoms of Gastroesophageal Reflux Disease

GERD: 2014 Dilemmas and Solutions. Ronnie Fass MD, FACP Professor of Medicine Case Western Reserve University

Review article: gastric acidity ) comparison of esomeprazole with other proton pump inhibitors

Review article: pharmacology of esomeprazole and comparisons with omeprazole

Helicobacter pylori Eradication Does Not Exacerbate Reflux Symptoms in Gastroesophageal Reflux Disease

Unmet Needs in the Management of Gastroesophageal Reflux Disease

Corpus gastritis is protective against reflux oesophagitis

Gastroesophageal reflux disease (GERD) is the. Gastroesophageal Reflux Disease in the Elderly A SPECIAL ARTICLE INTRODUCTION PATHOGENESIS

SASKATCHEWAN REGISTERED NURSES ASSOCIATION

GERD DIAGNOSIS & TREATMENT DISCLOSURES 4/18/2018

Disclosures. Proton Pump Inhibitors Deprescribing? Deprescribing PPI Objectives. Deprescribing. Proton Pump Inhibitors (PPI) 5/28/2018.

Characteristics of patients with erosive and nonerosive GERD in high-helicobacter-pylori prevalence region

Intragastric acidity during treatment with esomeprazole 40 mg twice daily or pantoprazole 40 mg twice daily a randomized, two-way crossover study

Effect of Helicobacter pylori infection and its eradication on nutrition

Esophageal Disorders. Learning Objectives. Introduction. Gastroesophageal Reflux Disease. Reza Shaker, MD, and Benson T.

GASTROESOPHAGEAL REFLUX DISEASE. William M. Brady

H elicobacter pylori is a human pathogen that causes

1. Introduction. Correspondence should be addressed to Wei-Chen Tai; Received 29 May 2013; Accepted 5 July 2013

Putting Chronic Heartburn On Ice

GI Pharmacology. Dr. Alia Shatanawi 5/4/2018

Increased gastric acid secretion after Helicobacter pylori eradication may be a factor for developing re ux oesophagitis

Assessment of symptomatic response as predictor of Helicobacter pylori status following eradication therapy in patients with ulcer

ACG Clinical Guideline: Diagnosis and Management of Gastroesophageal Reflux Disease

Management of dyspepsia and of Helicobacter pylori infection

GASTROINTESTINAL AND ANTIEMETIC DRUGS. Submitted by: Shaema M. Ali

Barrett s Esophagus: Old Dog, New Tricks

Helicobacter pylori: Diagnosis, treatment and risks of untreated infection

Functional Dyspepsia. Norbert Welkovics Heine van der Walt

Burning Issues in Gastroesophageal Reflux Disease (GERD)

Gastroesophageal Reflux Disease, Paraesophageal Hernias &

Prompt Upper Endoscopy Is an Appropriate Initial Management in Uninvestigated Chinese Patients With Typical Reflux Symptoms

Effect of Helicobacter pylori Eradication on Reflux Esophagitis Therapy: A Multi center Randomized Control Study

Achalasia is a rare disease with an annual incidence estimated REVIEWS. Erroneous Diagnosis of Gastroesophageal Reflux Disease in Achalasia

Obesity Is Associated With Increased Transient Lower Esophageal Sphincter Relaxation. Introduction. Predisposing factor. Introduction.

Original Article. Helicobacter pylori eradication and histopathological esophagitis in dyspeptic patients

Refractory GERD. Kenneth R. DeVault, MD, FACG President American College of Gastroenterology Chair Department of Medicine Mayo Clinic Florida

The usual dose is 40 mg daily with amoxycillin 1.5 g (750 mg b.d.) for 2 weeks. Up to 2 g/day of amoxycillin has been used in clinical trials.

Rpts. GENERAL General Schedule (Code GE) Program Prescriber type: Dental Medical Practitioners Nurse practitioners Optometrists Midwives

Gastro esophageal reflux disease DR. AMMAR I. ABDUL-LATIF

The Impact of Gender on the Symptom Presentation and Life Quality of Patients with Erosive Esophagitis and Non-Erosive Reflux Disease

ESOPHAGEAL CANCER AND GERD. Prof Salman Guraya FRCS, Masters MedEd

Barrett s Esophagus. Abdul Sami Khan, M.D. Gastroenterologist Aurora Healthcare Burlington, Elkhorn, Lake Geneva, WI

Module 2 Heartburn Glossary

Maastricht Ⅴ /Florence

PDF hosted at the Radboud Repository of the Radboud University Nijmegen

High Recurrence Rate of Idiopathic Peptic Ulcers in Long-Term Follow-up

Functional dyspepsia: relationship between clinical subgroups and Helicobacter pylori status in Western Turkey

GERD: A linical Clinical Clinical Update Objectives

Acid-Peptic Diseases of the Stomach and Duodenum Including Helicobacter pylori and NSAIDs Prof. Sheila Crowe

Eosinophilic Esophagitis (EoE)

A model of healing of Los Angeles grades C and D reflux oesophagitis: is there an optimal time of acid suppression for maximal healing?

History. Prevalence at Endoscopy. Prevalence and Reflux Sx. Prevalence at Endoscopy. Barrett s Esophagus: Controversy and Management

PEPTIC ULCER DISEASE JOHN R SALTZMAN, MD. Director of Endoscopy Brigham and Women s Hospital Professor of Medicine Harvard Medical School

Disclosures. Heartburn and Barrett s Esophagus. Heartburn and Barrett s Esophagus. GERD is common in the U.S. None

Helicobacter pylori Improved Detection of Helicobacter pylori

34th Annual Toronto Thoracic Surgery Refresher Course

Keywords: Helicobacter pylori; oesophagitis; gastro-oesophageal reflux disease; atrophic gastritis; gastric cancer

Table 2.9. Case control studies of helicobacter pylori infection and oesophageal adenocarcinoma

New developments in pathogenesis, gastric cancer. Matthias Ebert. II. Medizinische Klinik Klinikum rechts der Isar TU München

Helicobacter pylori and Gastroesophageal Reflux Disease

Systematic review: proton-pump inhibitor failure in gastro-oesophageal reflux disease where next?

Myogenic Control. Esophageal Motility. Enteric Nervous System. Alimentary Tract Motility. Determinants of GI Tract Motility.

Esophageal Motility. Alimentary Tract Motility

Index. Note: Page numbers of article titles are in boldface type.

CLINICAL CHARACTERISTICS, ENDOSCOPIC IMAGE OF GASTROESOPHAGEAL REFLUX DISEASE IN THE ELDERLY

Helicobacter 2008;13:1-6. Am J Gastroent 2007;102: Am J of Med 2004;117:31-35.

Symptoms suggestive of gastroesophageal reflux disease. Gastroesophageal Reflux Among Different Racial Groups in the United States

SUMMARY INTRODUCTION. Accepted for publication 8 July 2004

MEDICAL POLICY SUBJECT: MAGNETIC ESOPHAGEAL RING/ MAGNETIC SPHINCTER AUGMENTATION FOR THE TREATMENT OF GASTROESOPHAGEAL REFLUX DISEASE (GERD)

David Markowitz, MD. Physicians and Surgeons

Committee Approval Date: October 14, 2014 Next Review Date: October 2015

Gastrointestinal pathology 2018 lecture 4. Dr Heyam Awad FRCPath

Nexium 24HR. Tools and information for you and your pharmacy team NOW OTC FOR FREQUENT HEARTBURN. Consumer Healthcare Pfizer Inc.

Patients with established gastro-esophageal reflux disease might benefit from Helicobacter pylori eradication

New Developments in the Endoscopic Diagnosis and Management of Barrett s Esophagus

The Risk Factors and Quality of Life in Patients with Overlapping Functional Dyspepsia or Peptic Ulcer Disease with Gastroesophageal Reflux Disease

PPIs: Good or Bad? 1. Basics of PPIs. Gastric Acid Basics. Outline. Gastric Acid Basics. Proton Pump Inhibitors (PPI)

The interactions between Helicobacter pylori, acid, and

Drug Class Review on Proton Pump Inhibitors

Fecal incontinence causes 196 epidemiology 8 treatment 196

Peptic ulcer disease Disorders of the esophagus

Refractory GERD : case presentation and discussion

TBURN TBURN BURN ARTBURN EARTBURN EART HEARTBURN: HOW TO GET IT OFF YOUR CHEST

We are IntechOpen, the world s leading publisher of Open Access books Built by scientists, for scientists. International authors and editors

Mucosal breaks show same circumferential distribution in majority of patients with recurrent reflux esophagitis

Gastric juice acidity in upper gastrointestinal diseases

S. Sandberg-Lewis, ND, DHANP

Risk Factors for Helicobacter pylori Infection and Endoscopic Reflux Esophagitis in Healthy Young Japanese Volunteers

Proton Pump Inhibitors Drug Class Prior Authorization Protocol

GI update. Common conditions and concerns my patients frequently asked about

Correlation between gastric acid secretion and severity of acid reflux in children

Nexium 24HR Pharmacy Training

Page 1. Objectives. The Role of the Pharmacist as Gatekeeper to the Appropriate Use of OTC PPI Therapy in Frequent Heartburn

Evolution of gastro-oesophageal reflux disease over 5 years under routine medical care the ProGERD study

Alimentary Pharmacology & Therapeutics SUMMARY

Maximizing Outcome of Extraesophageal Reflux Disease. (GERD) is often accompanied

Transcription:

The Association and Clinical Implications of Gastroesophgeal Reflux Disease and H. pylori Maxwell M. Chait The relationship between GERD and H. pylori is complex and negatively associated with important implications for both individual patients and the nations of the world. Whereas the incidence of GERD and its complications, including Barrett s esophagus and adenocarcinoma of the esophagus and gastric cardia have increased, the incidence of H. pylori related gastroduodenal peptic ulcer disease and distal gastric adenocarcinoma has decreased in Western Europe and the United States. This suggests an inverse, negative, relationship between the two. H. pylori infection eradication does not cause GERD, but there is possibly a protective and negative effect of H. pylori in patients with GERD which is related to the virulence of the infecting strain and the distribution and severity of gastritis. It remains controversial whether or not to test and treat for the infection of H. pylori with respect to the direct management of GERD, because of its potentially protective effect. However, in patients who require long term therapy with PPI agents, a test and treat strategy may be appropriate, since PPI therapy might increase the risk of atrophic gastritis and its potential for B 12 malabsorption and gastric cancer in H. pylori infected individuals. If the prevalence of H. pylori decreases in the developing countries of the world, one may anticipate that there will be a decrease in incidence of cancer of the gastric body and antrum and an increase in the prevalence of GERD and incidence of adenocarcinoma of the esophagus and gastric cardia over the next few decades. This is an evolving area with important implications for individual patients as well as for the nations of the world. Maxwell M.Chait, M.D., F.A.C.P., F.A.C.G., Assistant Clinical Professor of Medicine, Columbia University College of Physicians and Surgeons, Hartsdale, New York. 40

INTRODUCTION Gastroesophageal reflux disease (GERD) is the most common upper gastrointestinal problem seen in clinical practice. It is estimated that 10% 20% of adults have symptoms at least once weekly and 15% 40% have symptoms at least once monthly (1). Complications of GERD vary from esophagitis and esophageal stricture to Barrett s esophagus and esophageal cancer. In contrast, H. pylori infection is the most common acquired factor in the etiology of gastritis and ulcers of the stomach and duodenum and in adenocarcinoma of the body and antrum of the stomach (2). Remarkably, as the prevalence of H. pylori and its complications has declined in the industrialized nations of the world, the incidence of GERD and its complications have increased, suggesting a negative association between the two disease states. H. pylori does not predispose to GERD. In fact, evidence indicates a possible protective role. But, there is a higher incidence of atrophic gastritis in patients taking proton pump inhibitor (PPI) agents with H. pylori infection. Therefore, the relationship between GERD and H. pylori is complex and may have important implications for the individual patient as well as for the nations of the world. PATHOPHYSIOLOGY OF GERD AND H. PYLORI GERD is predominantly a motility disorder. The abnormalities that appear to play a pathogenic role in GERD are a defective antireflux barrier, abnormal esophageal clearance, reduced salivary production, altered esophageal mucosal resistance, and delayed gastric emptying. Injury to the esophagus is due primarily to reflux of gastric acid and pepsin. In some cases, duodenogastric reflux of bile may cause the injury (3). Nocturnal gastroesophageal reflux is associated with more severe manifestations and esophageal and extraesophageal complications of GERD (4 6). The lower esophageal sphincter (LES) is the antireflux barrier. Abnormalities that make it dysfunctional promote acid reflux and the constellation of GERD problems. The most common cause of reflux episodes is transient LES relaxations, the drop in LES pressure not accompanied by swallowing. Multiple medications, such as nitrates, calcium channel blockers, benzodiazepines, anticholinergics, and antidepressants decrease LES pressure. The presence of a hiatal hernia impairs the function of the LES and may impair the clearance of refluxed acid from the distal esophagus (7). Reduction in esophageal acid clearance impaired by disturbances of esophageal motility and saliva production, delayed gastric emptying and duodenogastric reflux are also important factors. Although all ages are affected, the elderly tend to have more severe complications of GERD (8). GERD is also associated with the development of adenocarcinoma of the distal esophagus and gastric cardia. The pre-malignant lesion for the development of these cancers is Barrett s esophagus. H. pylori is highly associated with gastritis and gastroduodenal peptic ulcer disease. However, its effect on gastric acid depends upon the severity and distribution of gastritis within the stomach, with either increased, decreased, or unchanged gastric acid secretion. In H. pylori infection that is antrum predominant, there is hypergastrinemia, gastric hypersecretion and the propensity to gastroduodenal ulcer. All of the abnormalities resolve completely after eradication of the H. pylori organism except for the increased maximal acid output in response to gastrin which remains unchanged in these patients (9). In contrast, patients with corpus predominant infection tend to decreased gastric acid secretion which returns to normal with eradication of H. pylori. Basal gastric acid secretion is increased in subjects whose infection was eradicated, but not in those with persistent infection. However, basal and meal stimulated gastric acid secretion does not change after H. pylori eradication (10). Therefore, most studies suggest that patients with antrum predominant gastritis have increased gastric acid secretion that returns to normal after H. pylori eradication and patients with corpus predominant gastritis have reduced gastric acid secretion that returns to normal after eradication (11). Additionally, H. pylori may influence the gastric acid content of the gastric refluxate and affect patterns of gastritis and gastric acid secretion by release of ammonia by H. pylori, which may partially neutralize gastric acid (12). The amount of gastritis in the body of the stomach associated with lower gastric acidity returns to normal when H. pylori is eradicated. Also, the hypergastrinemia noted in these patients may lead to lower esophageal sphincter pressure (13). H. pylori, is associated with the development of atrophic gastritis and ade- (continued on page 45) 41

(continued from page 41) nocarcinoma of the body and antrum of the stomach. Atrophic gastritis is associated with B 12 malabsorption and is a pre-malignant lesion for the development of gastric cancer (2). Virulent strains of H. pylori, such as the cag A+ strain are associated with increased development of atrophic gastritis and gastric cancer (14,15). No causal relationship between H. pylori infection and gastroesophageal reflux disease has been demonstrated (16,17). However, H. pylori eradication may have a possible negative effect upon GERD. H. pylori eradication effects on the development of GERD would largely depend upon the patterns of gastritis and the disturbance of gastric acid secretion induced by the infection and could vary from individual to individual (18). For example, in patient s with H. pylori antrum predominant infection, which is associated with increased acid secretion, eradication of the infection will lower acid secretion and may improve the GERD. On the contrary, if the infection is corpus predominant, which is associated with reduced acid secretion, treatment of the infection will result in increased acid secretion which may induce or aggravate GERD. If H. pylori infection produces no overall disturbance of acid secretion, then treatment of the infection is unlikely to have an effect on GERD (19). Also, by treating H. pylori infection in a given population, the development or aggravation of GERD in that population will depend upon the pattern of H. pylori infection prevalent in that population. For example, studies from Asia, where H. pylori tends to be corpus predominant and associated with lower gastric acid secretion, show aggravation of esophagitis after H. pylori treatment (19,20). However, studies from Western Europe and the United States, where there is no regional preponderance of H. pylori infection, show conflicting results after H. pylori eradication (21,22). THE NEGATIVE RELATIONSHIP BETWEEN GERD AND H. PYLORI There is a substantial body of epidemiologic evidence that shows an inverse or negative association between the incidence of gastroesophageal reflux disease and H. pylori infection. The incidence of GERD in the industrialized countries of the Western world is quite high. For example, approximately 15% 40% of the adult U.S. population has heartburn symptoms. (1) Also, the incidence of GERD complications, especially adenocacinoma of the esophagus, is rising. In contrast the prevalence of H. pylori along with its complication of gastric adenocarcinoma is steadily decreasing in these nations. This is probably due to improvements in hygiene and socioeconomic factors and the treatment of H. pylori (23). Labenz, in a study of 6,125 patients with GERD, evaluated independent predictors of erosive disease, including male gender, increased body mass, regular alcohol intake and duration of disease. He showed that H. pylori had a protective effect in the subgroup analysis of patients with more severe Los Angeles C and D grade of esophagitis (24). Some studies have found that this negative association between H. pylori and GERD is more marked with more virulent caga+ strains of the infection. In another study, however, Kuipers did not observe a significant change in inflammation in patients with and without eradication of H. pylori in GERD patients, although there was a trend towards reduced control in the eradicated group (25). H. pylori may have a possible protective effect, especially the caga+ strain, for the development of the complications of GERD, including Barrett s esophagus and adenocarcinoma of the esophagus and gastric cardia. It is well known that complications of GERD are significantly more frequent in Caucasian rather than in African American or Asian populations, which is inversely proportional to the frequency of H. pylori infection. Several studies have reported a negative association between the prevalence of H. pylori, especially the caga+ strain, and the severe GERD complications of Barrett s esophagus and esophageal adenocarcinoma, which suggests a protective effect (26). A study from China revealed a stepwise relationship found between the increasing grade of esophagitis and decreasing prevalence of H. pylori (27). A Swedish study showed that H. pylori was associated with a significantly decreased risk of adenocarcinoma of the esophagus (27). A subgroup analysis showed that the negative association was only apparent for the caga+ strains of H. pylori (28). PROTON PUMP INHIBITORS AND H. PYLORI The most common and effective way of treating patients with GERD is by suppressing gastric acid 45

secretion with proton pump inhibitor (PPI) agents. The degree of inhibition of gastric acid secretion and elevation of gastric ph that are achieved by PPI agents are substantially greater in the H. pylori infected than uninfected patients and in H. pylori eradicated patients. For example, in H. pylori infected patients, Omeprazole at 20 mg per day produced a median gastric ph of 5.5. After eradication of H. pylori, the ph fell to 3.0 (29). Wu demonstrated that H. pylori eradication was the only predictor of treatment failure in patients after adjustments for age, sex, erosive esophagitis and hiatal hernia (30). Holtzman found that both the rate of healing of endoscopically proven esophagitis and the rate of resolution of symptoms was more rapid in the H. pylori infected patients treated with PPI agents, as compared to H. pylori uninfected patients (31). Two mechanisms are likely to contribute to the enhanced potency of PPI agents in the presence of H. pylori. PPI agents appear to transform the pattern of H. pylori gastritis into a corpus predominant pattern of gastritis, producing a marked increase in the inflammation in the acid secretion regions of the stomach which inhibits parietal cell function and gastric acid secretion. (32,33) This reduction of gastric acid supplements the pharmacological affect of PPI agents. In addition, ammonia produced by the H. pylori urease helps neutralize acid and thus contribute to the elevation of intragastric ph. Although both effects are probably minor, the increased efficacy of PPI agents may be associated with improved symptom control and more rapid healing of esophagitis. H. pylori infection has also been shown to affect the level of gastric acid secretion after discontinuing PPI therapy. For example, discontinuation of PPI therapy in some patients results in rebound hypersecretion of gastric acid which continues for several months in H. pylori eradicated patients. This may be the result of a trophic affect of the elevated gastrin level during H. pylori infection that exerts a prolonged effect upon the parietal cell mass. In contrast, some patients with H. pylori infection did not show a significant rebound hypersecretion. This protective effect may be explained by a corpus predominant pattern of gastritis induced by PPI agents in H. pylori infected subjects that produces a persistent inhibition of gastric acid secretion after stopping the drug and prevents rebound acid hypersecretion (34). As PPI agents change the H. pylori distribution to a corpus predominant pattern, it has been postulated that they may accelerate the development of atrophic gastritis and potentially increase the risk of gastric cancer as compared to uninfected patients. Virulent strains of H. pylori, such as caga+, have been reported to cause a greater risk of developing atrophic gastritis and gastric adenocarcinoma. Because of this potential threat of increased gastric cancer in these patients, a test and treat strategy has been proposed by the Maastricht Consensus Conference as well as by other investigators (35). However, PPI agents do not promote intestinal metaplasia (36). Thus, it remains unclear if long term use of PPI agents in H. pylori infected patients poses a significant risk for the development of gastric cancer in later life. CONCLUSION The relationship between GERD and H. pylori is complex and negatively associated with important implications for the individual and the populations of the world. The incidence of GERD and its complications, including adenocarcinoma of the esophagus, has increased in recent years, whereas the incidence of H. pylori related gastroduodenal peptic ulcer disease and distal gastric adenocarcinoma has decreased in the industrialized nations of the Western world, suggesting an inverse relationship between the two. Current data demonstrate that H. pylori infection eradication does not cause gastroesophageal reflux disease. However, there is possibly a protective and negative association between H. pylori infection, especially the more virulent caga+ strain, and the development of GERD and its complications of Barrett s esophagus and esophageal cancer that appears to depend upon the distribution and severity of the H. pylori gastritis. It remains controversial whether or not to treat for the infection of H. pylori with respect to the direct management of GERD, because of its potentially protective effect. However, in patients who require long term therapy with PPI agents, a test and treat strategy may be appropriate, since PPI therapy might increase the risk of atrophic gastritis with its potential for B 12 malabsorption and gastric cancer in H. pylori infected individuals. This may be more important in patients from non-industialized countries and Asia where there (continued on page 48) 46

(continued from page 46) is a higher incidence of corpus predominant type of H. pylori infection. If this were to be the case, then one may anticipate an increased prevalence of GERD and its complications of Barrett s esophagus and adenocarcinoma of the esophagus and gastric cardia in the developing countries of the world during the next few decades associated with a decreased prevalence of H. pylori infection and incidence of gastric cancer of the body and antrum. This is an evolving area with important implications for both individual patients as well as for the nations of the world. References 1. Howard PJ, Heading RC. Epidemiology of gastroesophageal reflux disease. World J Surg, 1992:16:288-293. 2. Graham DY. Helicobactor pylori infection in the pathogenesis of duodenal ulcer and gastric cancer: a model. Gastroenterology, 1997;113:1983-1991. 3. Traub M. The spectrum of the symptoms and presentations of gastroesophageal reflux disease. Gastroenterol Clin North Am, 1990;19:609-616. 4. Robertson D, Aldersley M, Shepherd H, et al. Patterns of acid reflux in complicated oesophagitis. Gut, 1987;28:1484-1488. 5. Lagergren J, Bergstrom R, Lindgren A, et al. Symptomatic gastroesophageal reflux is a risk factor for esophageal carcinoma. N Engl J Med, 1999;340:825-831. 6. Shaker R, Castell DO, Schoenfeld PS, et al. Nighttime heartburn is an under-appreciated clinical problem that impacts sleep and daytime function: the results of a Gallup survey conducted on behalf of the American Gastroenterological Association. Am J Gastroenterol, 2003;98:1487-1493. 7. Huang X, Zhu HM, Deng CZ, et al. Gastroesophageal reflux: the features in elderly patients. World J Gastroenterol, 1995;5(5):421-423. 8. Chait MM. Gastroesophageal reflux disease in the elderly. Practical Gastroenterology, 2005;29:(5)52-60. 9. Moss SF, Calam J. Acid secretion and sensitivity to gastrin in patients with duodenal ulcer: effect of eradication of H. pylori. Gut, 1993;34(7):888-892. 10. Gutierrez O, Melo M, Segura AM, et al. Cure of Helicobactor pylori infection improves gastric acid secretion in patients with corpus gastritis. Scand J Gastroenterol, 1997;32(7):664-668. 11. Haruma K, Mihara M, Okamoto E, et al. Eradication of Helicobactor pylori increases gastric acidity in patients with atrophic gastritis of the corpus evaluation of 24 hour ph monitoring. Gut, 1999;13:155-162. 12. Bercik P, Verdu E, Armstrong D, et al. The effects of ammonia on Omeprazole-induced reduction of gastric acidity in subjects with Helicobactor pylori infection. Am J Gastroenterol, 2000; 95:947-955. 13. El-Omar EM, Penman ID, Ardill JE, et al. Helicobactor pylori infection and abnormalities of acid secretion in patients with duodenal ulcer disease. Gastroenterology, 1991;109:681-691. 14. Kuipers EJ, Perez-Perez GI, Meuwissen SG, et al. Helicobactor pylori and atrophic gastritis: importance of the cag A status. J Natl Cancer Inst, 1995;87:1777-1780. 15. Van Doorn LJ, Figueiredo C, Sanna R, et al. Clinical relevance of cag A, vac A, and ice A status of Helicobactor pylori. Gastroentertology, 1998;115:58-66. 16. Tefera S, Hatlebakk JG, Berstad A. The effect of Helicobactor pylori eradication on gastro-oesophageal reflux. Aliment Pharmacol Ther, 1999;13:915-920. 17. Wu JC, Lai AC, Wong SK, et al. Dysfunction of oesophageal motility in Helicobactor pylori infected patients with reflux oesophagitis. Aliment Pharmacol Ther, 2001;15:1913-1919. 18. Labenz J, Blum AL Bayerdorffer E, et al. Curing Helicobactor pylori infection in patients with duodenal ulcer may provoke reflux esophagitis. Gastroenterology, 1997;112:1442-1447. 19. Hamada H, Haruma K, Mihara M, et al. High incidence of relux esophagitis after eradication therapy for Helicobactor pylori: impacts of hiatal hernia and corpus gastritis. Aliment Pharmacol Ther, 2000;14:729-735. 20. Take S, Mizuno M, Ishiki K, et al. The effect of eradicating Helicobactor pylori on the development of gastric cancer in patients with peptic ulcer disease. Am J Gastroenterol, 2005:100: 1037-1042. 21. Vakil N, Hahn B, McSorley. Recurrent symptoms and gastroesophageal reflux disease in patients with duodenal ulcer treated for Helicobactor pylori infection. Aliment Pharmacol Ther, 2000; 14:45-51. 22. Fallone C, Barkun A, Friedman G, et al. Is Helicobactor pylori eradication associated with gastroesophageal reflux disease? Am J Gastroenterol, 2000;95:914-920. 23. Everhaart JE. Recent developments in the epidemiology of Helicobactor pylori. Gastroenterol Clin N Am, 2000;29:539-578. 24. Labenz J, Jespersen D, Kulig M, et al. Risk factors for erosive esophagitis: a multivariate analysis based on the ProGERD study initiative. Am J Gastroenterol, 2004;99:1652-1656. 25. Kuipers EJ, Nelis GF, Klinkenberg-Knol EC, et al. Cure of Helicobactor pylori infection in patients with reflux esophagitis treated with long term omeprazole reverses gastritis without exacerbation of reflux disease: results of a randomized controlled trial. Gut, 2004;53:12-20. 26. Sharma P. Recent advances in Barrett s esophagus: short segment Barrett s esophagus and cardia intestinal metaplasia. Semin Gastroent Dis, 1999;10:93-102. 27. Zhang J, Chen XL, Wang KM, et al. Relationship of gastric Helicobactor pylori infection to Barrett s esophagus and gastroesophageal reflux disease in Chinese. World J Gastroenterol, 2004;10:672-675. 28. Ye W, Held M, Lagergren J, et al. Helicobactor pylori infection and gastric atrophy: risk of adenocarcinoma and squamous cell carcinoma of the esophagus and adenocarcinoma of the gastric cardia. J Natl Cancer Inst, 2004;96:387-296. 29. Labenz J, Tillenburg B, Peitz U, et al. Helicobacter augments the ph-increaseing effect of omeprazole in patients with duodenal ulcer. Gastroenterology, 1996;110:725-732. 30. Wu JCY, Chan FKL, Ching JYL, et al. Effect of Helicobactor pylori on the treatment of gastroesophageal reflux disease: a doubleblind, placebo-controlled, randomized trial. Gut, 2004;53:174-179. 31. Holtmann G, Cain C, Malfertheiner P. Gastric Helicobacter infection accelerates healing of reflux esophagitis during treatment with the proton inhibitor pantoprazole. Gastroenterology, 1999; 117:11-16. 32. Gillen D, Wirz AA, Neithercut WD, et al. Helicobactor pylori potentiates the inhibition of gastric acid secretion by omeprazole. Gut, 1999;44:468-475. 33. Kuipers EJ, Uyterlinde AM, Penna AS, et al. Increase of Helicobactor pylori-associated corpus gastritis during acid suppressive therapy: implications for long term safety. Am J Gastroenterol, 1995;90:1401-1406. 34. Sachs G. Gastritis, Helicobactor pylori, and proton pump inhibitors. Gastroenterology, 1997;112: 487-495. 35. Malfertheiner P, Megraud F, O Morain C. Current European concepts in the management of Helicobactor pylori infection. The Maastricht consensus report. Gut, 1997;41:8-13. 36. Kuipers EJ, Lundell L, Klinkenberg EC, et al. Atrophic gastritis and Helicobacter infection in patients with reflux esophagitis treated with omeprazole or fundoplication. N Engl J Med, 1996;334:1018-1022. 48