Derek Gillen

Helicobacter pylori infection and chronic gastric acid hyposecretion

BACKGROUND & AIMS We have identified a subgroup of Helicobacter pylori-infected subjects with low or absent gastric acid output. The aim of this study was to document the morphological and functional abnormalities in these subjects and to assess the effect of eradicating the infection. METHODS The 16 hypochlorhydric subjects (6 men) had a mean age of 55 years (range, 36-79 years). They underwent a 14C-urea breath test, H. pylori serology, fasting gastrin, gastric autoantibodies, gastroscopy with antral and body biopsies, and measurement of peak acid output to pentagastrin (PAO(PG)). Their histology was compared with that of age- and sex-matched duodenal ulcer and nonulcer dyspepsia patients (16 each). H. pylori infection was eradicated in the hypochlorhydric subjects, and the investigations were repeated 6 months later. RESULTS Compared with controls, the hypochlorhydric subjects had less dense H. pylori colonization, body-predominant colonization and gastritis, and increased prevalence of body atrophy and intestinal metaplasia. Median PAO(PG) before eradication in the hypochlorhydric subjects was 1.1 mmol/h and increased to 12.6 mmol/h after eradication (P < 0.001), with no significant change in body atrophy or intestinal metaplasia. CONCLUSIONS In some subjects, chronic H. pylori infection produces a body-predominant gastritis and profound suppression of gastric acid secretion that is partially reversible with eradication therapy.

Increased prevalence of precancerous changes in relatives of gastric cancer patients: critical role of H. pylori

BACKGROUND & AIMS Helicobacter pylori is believed to predispose to gastric cancer by inducing gastric atrophy and hypochlorhydria. First-degree relatives of patients with gastric cancer have an increased risk of developing gastric cancer. The aim of this study was to determine the prevalence of atrophy and hypochlorhydria and their association with H. pylori infection in first-degree relatives of patients with gastric cancer. METHODS H. pylori status, gastric secretory function, and gastric histology were studied in 100 first-degree relatives of patients with noncardia gastric cancer and compared with those of controls with no family history of this cancer. RESULTS Compared with healthy controls, relatives of patients with gastric cancer had a higher prevalence of hypochlorhydria (27% vs. 3%) but a similar prevalence of H. pylori infection (63% vs. 64%). Relatives of cancer patients also had a higher prevalence of atrophy (34%) than patients with nonulcer dyspepsia (5%) matched for H. pylori prevalence. Among the relatives of cancer patients, the prevalence of atrophy and hypochlorhydria was increased only in those with evidence of H. pylori infection, was greater in relatives of patients with familial cancer than in relatives of sporadic cancer index patients, and increased with age. Eradication of H. pylori infection produced resolution of the gastric inflammation in each subject and resolution of hypochlorhydria and atrophy in 50% of the subjects. CONCLUSIONS Relatives of patients with gastric cancer have an increased prevalence of precancerous gastric abnormalities, but this increase is confined to those with H. pylori infection. Consequently, prophylactic eradication of the infection should be offered to such subjects.

Rebound hypersecretion after omeprazole and its relation to on-treatment acid suppression and Helicobacter pylori status

BACKGROUND & AIMS There have been conflicting reports regarding acid secretion after treatment with omeprazole. This study examined acid secretion after treatment with omeprazole and its relation to Helicobacter pylori status and on-treatment gastric function. METHODS Twelve H. pylori-negative and 9 H. pylori-positive subjects were examined before, on, and at day 15 after an 8-week course of 40 mg/day omeprazole. On each occasion, plasma gastrin, intragastric pH, and acid output were measured basally and in response to increasing doses of gastrin 17. RESULTS In the H. pylori-negative subjects at day 15 after omeprazole treatment, basal acid output was 82% higher (P < 0.007) and maximal acid output 28% higher (P < 0.003) than before omeprazole. The degree of increase in maximal acid output was related to both on-treatment pH and on-treatment fasting gastrin levels, being 48.0% in subjects with an on-treatment pH of >4 vs. 21. 0% in those with a pH of <4 (P < 0.02) and 49.2% in subjects with an on-treatment gastrin of >25 ng. L-1 vs. 19.8% in those with a fasting gastrin of <25 ng. L-1 (P < 0.006). At day 15 after omeprazole treatment, the H. pylori-positive subjects showed a heterogeneous response with some having increased acid output and others persisting suppression. CONCLUSIONS Rebound acid hypersecretion occurs in H. pylori-negative subjects after omeprazole treatment. Its severity is related to the degree of elevation of pH on treatment. Persisting suppression of acid secretion masks the phenomenon in H. pylori-positive subjects.

Randomised trial of endoscopy with testing for Helicobacter pylori compared with non-invasive H pylori testing alone in the management of dyspepsia

Abstract Objective: To compare the efficacy of non-invasive testing for Helicobacter pylori with that of endoscopy (plus H pylori testing) in the management of patients referred for endoscopic investigation of upper gastrointestinal symptoms. Design: Randomised controlled trial with follow up at 12 months. Setting: Hospital gastroenterology unit. Participants: 708 patients aged under 55 referred for endoscopic investigation of dyspepsia, randomised to non-invasive breath test for H pylori or endoscopy plus H pylori testing. Main outcome measure: Glasgow dyspepsia severity score at one year. Use of medical resources, patient oriented outcomes, and safety were also assessed. Results: In 586 patients followed up at 12 months the mean change in dyspepsia score was 4.8 in the non-invasive H pylori test group and 4.6 in the endoscopy group (95% confidence interval for difference −0.7 to 0.5, P=0.69). Only 8.2% of patients followed up who were randomised to breath test alone were referred for subsequent endoscopy. The use of non-endoscopic resources was similar in the two groups. Reassurance value, concern about missed pathology, overall patient satisfaction, and quality of life were similar in the two groups. The patients found the non-invasive breath test procedure less uncomfortable and distressing than endoscopy with or without sedation. No potentially serious pathology requiring treatment other than eradication of H pylori was missed. Conclusion: In this patient group, non-invasive testing for H pylori is as effective and safe as endoscopy and less uncomfortable and distressing for the patient. Non-invasive H pylori testing should be the preferred mode of investigation. What is already known on this topic Endoscopy is a commonly used investigation for upper gastrointestinal symptoms, but its effectiveness has been questioned Non-invasive testing for Helicobacter pylori has been shown to predict endoscopic diagnosis in patients with dyspepsia What this study adds In patients less than 55 years of age with uncomplicated dyspepsia, non-invasive testing for H pylori is as effective and as safe as endoscopy Non-invasive H pylori testing is as reassuring to the patient as endoscopy and is less uncomfortable and distressing

Helicobacter pylori infection potentiates the inhibition of gastric acid secretion by omeprazole.

BACKGROUND Omeprazole has a greater intragastric pH elevating effect in Helicobacter pylori positive than negative subjects. Ammonia production byH pylori has been suggested as a probable mechanism. AIMS To assess the effect ofH pylori status on gastric acid secretion during omeprazole treatment, and to examine the possible role of ammonia neutralisation of intragastric acid in increased omeprazole efficacy in infected subjects. METHODS TwentyH pylori positive and 12H pylori negative healthy volunteers were examined before and six to eight weeks after commencing omeprazole 40 mg/day. On both occasions plasma gastrin and acid output were measured basally and in response to increasing doses of gastrin 17 (G-17). Gastric juice ammonium concentrations were also measured. RESULTS Prior to omeprazole, measurements were similar in the H pyloripositive and negative subjects. During omeprazole, median basal intragastric pH was higher in the H pyloripositive (7.95) versus negative (3.75) subjects (p<0.002). During omeprazole basal, submaximal (180 pmol/kg/h G-17), and maximal acid outputs (800 pmol/kg/h G-17) were lower in H pylori positive subjects (0.0, 3.6, 6.0 mmol/h respectively) versus negative subjects (0.3, 14.2, 18.6 mmol/h) (p<0.03 for each). This effect was not explained by neutralisation by ammonia. CONCLUSION The presence ofH pylori infection leads to a more profound suppression of acid secretion during omeprazole treatment. The effect cannot be explained by neutralisation of intragastric acid by bacterial ammonia production and its precise mechanism has to be explained.

Helicobacter pylori gastritis and gastric physiology.

It is now recognized that Helicobacter pylori infection exerts profound and diverse effects on gastric acid secretory function and that the alterations in acid secretion depend on the pattern of gastritis caused by the infection. In patients with an antral predominant nonatrophic gastritis, there is acid hypersecretion leading to duodenal ulcer disease. In patients with an atrophic pangastritis, there is markedly reduced acid secretion and increased risk for gastric cancer. It is now recognized that acid secretion also modifies H. pylori gastritis and a persons premorbid acid secretory status may be an important factor in determining the pattern of gastritis that an individual develops. This two-way interaction between H. pylori gastritis and gastric acid secretion is important in understanding the role of H. pylori infection in the response to proton-pump inhibitor therapy: It explains the more profound control of gastric acid secretion in H. pylori-positive patients and why rebound acid hypersecretion is confined to H. pylori-negative subjects.

DOES CONCERN ABOUT MISSING MALIGNANCY JUSTIFY ENDOSCOPY IN UNCOMPLICATED DYSPEPSIA IN PATIENTS AGED LESS THAN 55

Objective: There is increasing interest in using noninvasive H. pylori testing rather than endoscopy in determining the management of younger patients presenting with dyspepsia. However, there is concern that this approach may result in missing potentially curable malignancy. The aim of the study was therefore to assess whether concern over occult malignancy is valid in patients aged <55 yr presenting with uncomplicated dyspepsia. Methods: A predetermined questionnaire was used to review the case notes of patients aged <55 yr who had presented with esophageal or gastric cancer between 1989 and 1993 within the Greater Glasgow Health Board population of 940,000. Results: A total of 169 patients aged <55 yr were diagnosed to have gastroesophageal malignancy over the 5-yr period, representing an incidence of about 1 per 28,000 total population/yr. There were only five patients who were found to have upper GI malignancy when undergoing upper GI investigation in the absence of sinister symptoms. This represents an incidence of underlying malignancy in patients of <55 yr with uncomplicated dyspepsia of 1.06 per million total population/yr. Of these five patients, all had lymph node metastases at diagnosis and four had died between 2 months and 3 yr of follow-up. Conclusions: Upper GI malignancy is extremely rare in patients <55 yr presenting with uncomplicated dyspepsia and, when found, is usually incurable. Consequently, concern about missing underlying curable malignancy is not a valid indication for endoscoping patients <55 yr presenting with uncomplicated dyspepsia.

The acid response to gastrin distinguishes duodenal ulcer patients from Helicobacter pylori–infected healthy subjects

BACKGROUND & AIMS Helicobacter pylori-induced hypergastrinemia is accompanied by increased acid secretion in patients with duodenal ulcer (DU) but not in infected healthy volunteers. The aim of this study was to investigate the mechanism underlying this difference. METHODS Thirty-four H. pylori-negative and 20 H. pylori-positive healthy volunteers and 15 H. pylori-positive patients with DU were studied. Maximal acid output and sensitivity to gastrin (gastrin concentration required to achieve 50% maximal acid output) were assessed by examining the dose response to gastrin 17. Inhibitory control was tested by comparing the maximal acid response to cholecystokinin octapeptide with that for gastrin 17. RESULTS Sensitivity to gastrin was similar in patients with DU (median, 69.5 ng.L-1; range, 26.2-142) and H. pylori-negative healthy volunteers (median, 82.2 ng.L-1; range, 17.7-410); H. pylori-positive healthy volunteers were less sensitive than either (164.5 ng.L-1; range, 44.8 to > 3360 ng.L-1). Patients with DU had higher maximal acid output (51.2 mmol.h-1; range, 30.8-73.7 mmol.h-1) than either infected healthy volunteers (37.8 mmol.h-1; range, 0.0-65.0 mmol.h-1; P < 0.04) or uninfected healthy volunteers (35.3 mmol.h-1; range, 21.3-67.3 mmol.h-1; P < 0.002). The maximal acid output in both groups of healthy subjects was similar. The proportion of maximal acid output to gastrin 17 achieved by cholecystokinin was similar in patients with DU (36.6%; range, 21.5%-58.2%) and H. pylori-negative healthy volunteers (28.7%; range, 5.9%-85.8%). CONCLUSIONS A combination of decreased sensitivity to gastrin in infected healthy volunteers and increased maximal acid secretory capacity in patients with DU underlies their different acid response to H. pylori-induced hypergastrinemia.

The Helicobacter pylori breath test: a surrogate marker for peptic ulcer disease in dyspeptic patients.

BACKGROUND: There is interest in noninvasive H pylori testing as a means of predicting diagnosis and determining management in dyspeptic patients. AIMS: To assess the value of the 14C urea breath test as a predictor of peptic ulcer disease in patients presenting with dyspepsia. PATIENTS AND METHODS: 327 consecutive patients referred for investigation of dyspepsia had a 14C urea breath test performed before endoscopy. Patients were not included if they had previously confirmed ulcer disease, previous gastric surgery, or were taking non-steroidal anti-inflammatory drugs. RESULTS: Of the 182 patients with a positive 14C urea breath test, duodenal and/or gastric ulcers were present in 45% and erosive duodenitis in a further 2%. Oesophagitis was present in 12% of the breath test positive patients with two thirds of the oesophagitis patients having co-existent ulcer disease. The prevalence of ulcer disease in the H pylori positive dyspeptic patients was independently related to smoking and previous investigation status. If previously uninvestigated, the prevalence of ulcers was 67% in smokers and 46% in non-smokers. If previous upper gastrointestinal investigations were negative, the prevalence of ulcers was 53% in smokers and 28% in non-smokers. Of the 136 patients with a negative breath test, only 5% had peptic ulcers. The most frequent endoscopic finding in these H pylori negative subjects was oesophagitis, being present in 17%. CONCLUSIONS: This study demonstrates that a positive H pylori test is a powerful predictor of the presence of underlying ulcer disease in dyspeptic patients, especially if smokers, and that a negative H pylori test is a powerful predictor of the absence of ulcer disease. It also indicates that a negative upper gastrointestinal investigation does not preclude subsequent presentation with ulcer disease.

Gastric histology, serological markers and age as predictors of gastric acid secretion in patients infected with Helicobacter pylori.

Background: Acid secretion is intimately associated with most upper gastrointestinal diseases. Helicobacter pylori infection is a major environmental factor modifying acid secretion. Aim: To study the association between the pattern of H pylori gastritis and gastric secretory function in a large number of subjects without specific upper gastrointestinal disease. Methods and materials: Maximal acid output (MAO) was measured in 255 patients with dyspepsia showing normal endoscopy. Activity and severity of gastritis, atrophy and H pylori infection were assessed in body and antral biopsies. The correlations of histological parameters as well as age, sex, height, weight, smoking, serum gastrin, pepsinogen I and II, and their ratio with MAO were determined. Multiple linear regression was used to show the best possible predictors of MAO. Results: Negative relationships: Body atrophy and body-combined (active and chronic) inflammatory scores showed a potent inverse correlation with MAO (correlation coefficients (CC) 0.59 and 0.50, respectively). Body:antral chronic gastritis ratio and body:antral combined inflammation ratio (both with CC = 0.49) and age (CC = 0.44) were also inversely correlated with MAO. Intestinal metaplasia at both antral and body sites had negative relationships with acid output with CC = 0.23 and 0.20, respectively. Positive relationships: Serum pepsinogen I, body H pylori density:combined inflammation ratio and pepsinogen I:II ratio with CC of 0.38, 0.38 and 0.30, respectively, correlated with MAO. The H pylori density: combined inflammation of both antrum and body positively correlated with MAO (CC = 0.29 and 0.38, respectively). Male sex and patient height also positively correlated with acid output. Modelling showed that body combined inflammatory score, body atrophy, age and serum pepsinogen I are independent predictors of acid output (R2 = 0.62). Conclusion: Combination of body gastritis, body atrophy, age and serum pepsinogen I can be used as predictors of acid-secretory state in populations infected with H pylori.