Epidemiologie und Spontanverlauf der Refluxkrankheit

Review article: trials on reflux disease -- the role of acid secretion and inhibition

The importance of gastric acid in the pathophysiology of gastro-oesophageal reflux disease is substantiated by the extraordinary therapeutic success of acid inhibition in the management of the disease. The influence of many risk factors for gastro-oesophageal reflux disease is also mediated through their effect on gastric acid secretion and acid reflux. Helicobacter pylori reduces the risk of gastro-oesophageal reflux disease by causing corpus gastritis and reducing gastric acid output. The geographical and temporal trends of H. pylori infection in human populations and its influence on gastric acid secretion are responsible for much of the apparent epidemiology of gastro-oesophageal reflux disease. On average, intra-oesophageal exposure to acid is higher in patients who respond poorly to antisecretory medication. It also tends to increase with increasing severity of reflux disease. However, gastric acid secretion and intra-oesophageal acid exposure vary markedly in reflux patients. The degrees of gastric or intra-oesophageal acidity do not allow the prediction of the presence or severity of gastro-oesophageal reflux disease in the individual subject. The many clinical trials on gastro-oesophageal reflux disease indicate that the reflux of gastric acid constitutes an essential mechanism in the development of this disease, but that additional and partly unknown risk factors must contribute to its aetiology and promote its occurrence in the individual patient.

[Bronchopulmonary manifestations of gastroenterologic and hepatic diseases]

Topics of this review are the bronchopulmonary manifestations of gastroesophageal reflux disease, cirrhosis of the liver and chronic inflammatory bowel diseases. About 20% of patients with chronic obstructive airway disease show evidence of gastroesophageal reflux disease. Reflux bronchoconstriction seems to be of greater importance than microaspiration. First studies show the positive effects of acid inhibition by proton pump inhibitors on pulmonary symptoms. Hepatorenal syndrome is characterized by arterial hypoxemia with PaO2-values < 70 mm Hg. Different mediators (endotoxins, amines, polypeptides or allergens) are discussed. Furthermore, elevated levels of prostacycline, atrial natriuretic factor and platelet activating factor have been described. Recently published studies focused on the role of nitric oxide (NO). Patients with cirrhosis of the liver show a higher rate of a pathologically elevated airway resistance which might be induced by a reduced histamine clearance. Ascites leads to reversible restrictive airway disease. Bronchopulmonary manifestations in chronic inflammatory bowel diseases include obstructive and restrictive airway diseases, vascular or serosal changes and show low clinical evidence. In contrast, pathological changes of the common function tests were found in 30 to 50%. These findings may be induced by circulating immune complexes, vasculitis, increased permeability or a combined immune reaction of both, the bronchial and intestinal mucosa. Undesired effects of salicylates should be taken into account. This review shows that bronchopulmonary manifestations in diseases of the Gl-tract or the liver are more common than usually known and should be taken into clinical consideration.

Prognostic factors influencing relapse of oesophagitis during maintenance therapy with antisecretory drugs: a meta-analysis of long-term omeprazole trials

BACKGROUND

This meta-analysis investigated factors that may affect the risk of relapse of oesophagitis, and evaluated the predictive value of symptoms for the presence of relapse during long-term treatment.

METHODS

Individual data from 1154 patients included in five independently conducted, randomized, long-term clinical trials of the efficacy of different dosage regimens of omeprazole, standard ranitidine treatment and placebo for the prevention of relapse of oesophagitis were pooled for this meta-analysis. The therapeutic regimens studied were omeprazole 20 mg o.m. (OME20) in 366 patients, omeprazole 10 mg o.m. (OME10) in 225 patients, omeprazole 20 mg weekends (OMEW) in 235 patients, ranitidine 150 mg b.d. (RAN) in 179 patients, or placebo (PLA) in 149 patients.

RESULTS

OME20 maintained 82.4% (95% CI: 78.2-86.6%) of patients in endoscopic remission over the 6-month period compared to 71.9% (95% CI: 65.5-78.3%) for OME10, 52.3% (95% CI: 44.4-60.1%) for RAN, 42.7% (95% CI: 35.8-49.5%) for OMEW, and 10.6% (95% CI: 5.0-16.3%) for PLA. A Cox's regression analysis of time to recurrence of oesophagitis showed that four factors were associated with a higher relapse rate during placebo and active maintenance therapy: (a) pre-treatment severity of oesophagitis (P < 0.0001), (b) young age (P = 0.01), (c) non-smoking (P = 0.02) and (d) moderate/severe regurgitation before entry into the trials (P = 0.03). Asymptomatic relapse of oesophagitis was uncommon, being found in only 8.6% of the patients.

CONCLUSIONS

Maintenance treatment with omeprazole 10 and 20 mg daily is superior to all other regimens tested, and is only marginally influenced by the pretreatment severity of oesophagitis. Age contributes to the factors that influence the outcome during long-term treatment with omeprazole. Symptom relief is highly predictive for the maintenance of healing.

A porcine model of gastroesophageal reflux

The exact mechanism by which the lower esophageal sphincter (LES) prevents gastroesophageal reflux disease (GERD) remains controversial. The two main reasons for this controversy are the lack of a good animal model and the only recent technologic advances in this field. To date, no animal models exist that use 24-hour pH studies, manometry, and endoscopy in evaluating GERD. The purpose of this study is to create a good model of GERD that uses this technology and to delineate the true nature of the LES more clearly. Recently, three-dimensional vector volume studies were performed and through detailed, cadaveric, anatomic studies, the vector volume profiles were correlated to distinct groups of muscle fibers at the gastroesophageal junction in humans. In this study, an anatomic analysis of the porcine gastroesophageal junction revealed an arrangement of muscle fibers similar to that in humans. A myectomy of the porcine oblique fibers was performed in nine piglets weighing 10 to 12 kg. The authors were able to demonstrate manometric attenuation of the porcine LES, gastroesophageal reflux by ambulatory 24-hour pH monitoring (P < 0.0025), and the creation of GERD by documenting esophagitis grossly and histologically. In conclusion, this model of GERD works and lends further support to the notion that the LES may be a discrete anatomic entity.

Hospital discharges resulting from esophagitis among Medicare beneficiaries

Despite the frequent occurrence of gastroesophageal reflux disease, until now only very few studies have dealt with the epidemiology of this common disorder. The Health Care Financing Administration complies annually 10 million records of all hospital discharges among Medicare beneficiaries distributed throughout the United States. The purpose of the present study was to take advantage of this large data set and analyze the demographic characteristics of patients discharged with esophagitis, esophageal ulcer, or esophageal stricture. The hospital discharge rates of all three diagnoses showed an age-related rise, the rise being most pronounced for esophageal stricture and, less significant, esophageal ulcer. The marked age dependency of esophageal stricture and ulcer may reflect the time necessary for complications to develop. While simple esophagitis affected women more frequently than men, significantly more men contracted its severe forms involving ulcers and strictures. All forms were more common in whites than blacks, and living in the southern parts of the United States was associated with an increased risk for esophagitis and strictures. The data suggest that besides varying exposure to environmental risk factors, differences in the pathophysiology among demographically stratified groups contribute to the occurrence of esophagitis.

Epidemiology of reflux disease and reflux esophagitis

Symptomatic gastroesophageal reflux is a common medical problem. But only few data exist on the epidemiology of reflux disease (without inflammation) and reflux esophagitis. The literature is critically reviewed and ecological causes of gastroesophageal reflux are discussed. The prevalence of reflux esophagitis in Western countries is estimated to be 2% and that of reflux disease 5%. Sparse reports exist on the natural history of both diseases. They appear to have little if any effect on life expectancy. The main complications of reflux esophagitis are Barrett's esophagus, peptic stricture, ulceration and bleeding.

Esophageal disorders in the etiology and pathophysiology of dyspepsia

Dyspepsia may be caused by reflux esophagitis. We evaluated the symptoms of 45 patients aged 52 +/- 14 years who had a follow-up of 1 to 5 years. Endoscopy and histology demonstrated microscopic inflammation in 14, isolated mucosal defects in 12 and severe inflammation in 19 of the 45 patients. Belching was the leading symptom in patients with microscopic and severe esophagitis, heartburn in mild esophagitis. Upper abdominal pain, nausea and vomiting were present in 31%, 24% and 22% of the patients, respectively. Thus, reflux esophagitis is frequently accompanied by symptoms of dyspepsia which resemble those of other causes of dyspepsia. In contrast, disorders of gastric and intestinal motility may be associated with esophageal motor disturbances, particularly in gastric dysrhythmia, diabetic gastroenteropathy, irritable bowel syndrome, and idiopathic intestinal pseudo-obstruction. How much the esophagus contributes to the clinical symptomatology of dyspepsia awaits further elucidation.