Oesophagitis, signs of reflux, and gastric acid secretion in patients with symptoms of gastro-oesophageal reflux disease

In a study comprising 100 patients referred to a surgical clinic with symptoms suggestive of gastro-oesophageal reflux disease the value of different diagnostic procedures was investigated. Positive acid perfusion and 24-h pH tests were the commonest findings. Forty-nine per cent showed a normal oesophageal mucosa or diffuse oesophagitis at endoscopy. The severity of heartburn and regurgitation did not differ between patients with normal oesophageal mucosa and oesophagitis of various severities. The severity of macroscopic oesophagitis was significantly correlated to the total reflux time, the presence of reflux or a hiatal hernia at radiology, an open cardia or reflux at endoscopy, pressure transmission or reflux and low lower oesophageal sphincter pressure at manometry. Gastric hypersecretion was found in 66% of the patients. Gastric acid secretion was not correlated to the severity of oesophagitis or to the findings at 24-h pH test. In patients with severe oesophagitis the sensitivity for radiologic, manometric, and endoscopic signs of incompetence of the gastro-oesophageal junction was 94%.     

Oesophagitis,Signs of Reflux,and Gastric Acid Secretion in Patients with Symptoms of Gastro-Oesophageal Reflux Disease

Johansson K-E, Ask P, Boeryd B, Fransson S-G, Tibbling L. Oesophagitis, signs of reflux, and gastric acid secretion in patients with symptoms of gastro-oesophageal reflux disease. Scand J Gastroenterol 1986, 21, 837-847

In a study comprising 100 patients referred to a surgical clinic with symptoms suggestive of gastro-oesophageal reflux disease the value of different diagnostic procedures was investigated. Positive acid perfusion and 24-h pH tests were the commonest findings. Forty-nine per cent showed a normal oesophageal mucosa or diffuse oesophagitis at endoscopy. The severity of heartburn and regurgitation did not differ between patients with normal oesophageal mucosa and oesophagitis of various severities. The severity of macroscopic oesophagitis was significantly correlated to the total reflux time, the presence of reflux or a hiatal hernia at radiology, an open cardia or reflux at endoscopy, pressure transmission or reflux and low lower oesophageal sphincter pressure at manometry. Gastric hypersecretion was found in 66% of the patients. Gastric acid secretion was not correlated to the severity of oesophagitis or to the findings at 24-h pH test. In patients with severe oesophagitis the sensitivity for radiologic, manometric, and endoscopic signs of incompetence of the gastro-oesophageal junction was 94%.     

4 Is functional dyspepsia largely explained by gastro-oesophageal reflux disease?

Functional dyspepsia is a chronic disorder of unknown aetiology. The lack of endoscopic abnormalities in patients with this disorder has led many physicians to believe that gastrooesophageal reflux disease may be responsible for most symptoms. Our group has addressed this issue, by pathophysiological studies in a large cohort of Dundee patients with persistent dyspeptic symptoms. Peptic ulcer and gallstones were excluded in all patients by appropriate tests. Ambulatory pH monitoring showed oesophageal acid reflux that lay above the conventional diagnostic threshold in approximately 20% of patients. This subset was diagnosed as having gastro-oesophageal reflux disease.In the remainder, moderate or severe reflux-like symptoms were reported by approximately 44% patients, who were categorized as reflux-like functional dyspepsia. Reflux symptoms were mild or absent in 36% patients, who were categorized as non-reflux-like dyspepsia. While oesophageal pH profiles lay within the conventional normal range in both of these functional dyspepsia subgroups, patients with reflux-like functional dyspepsia had significantly greater acid exposure values, including total oesophageal acid exposure time, percentage time at a pH of less than 4.0, DeMeester scores and pain reflux event correlation. Hence patients with reflux-like functional dyspepsia have oesophageal acid exposure that lies below the diagnostic threshold for gastro-oesophageal reflux disease but exceeds that of patients with non-reflux dyspepsia. The high pain/reflux event correlation in reflux-like functional dyspepsia suggests that subthreshold oesophageal acid exposure may be associated with troublesome reflux symptoms.     

Ambulatory 24 hour intraoesophageal pH and pressure recordings v provocation tests in the diagnosis of chest pain of oesophageal origin.

Fifty patients with non-cardiac chest pain underwent 24 hour intraoesophageal pH and pressure recording and provocation tests to determine the relative value of both techniques in establishing the oesophageal origin of the chest pain. Twenty six patients (52%) had at least one positive provocation test: the acid perfusion test was positive related in 18 patients (36%), the edrophonium test in 16 patients (32%), the vasopressin test in five patients (10%), and the balloon distension test (performed in only 20 patients) in one (5%). The 24 hour pH and pressure recording correlated spontaneous chest pain attacks with abnormal motility or gastro-oesophageal reflux in 19 patients (38%). Fourteen of these patients also had at least one positive provocation test. Therefore, 24 hour pH and pressure recordings are only slightly better than a set of provocation tests in identifying the oesophagus as the cause of chest pain (10% diagnostic gain). In the case of oesophageal chest pain, however, 24 hour recording appeared to be the only way to identify the nature of the underlying oesophageal abnormality that caused the spontaneous pain attacks--for example, gastro-oesophageal reflux, motility disorders, or irritability of the oesophagus.     

Manometric and pH-metric features in gastro-oesophageal reflux disease patients with and without Helicobacter pylori infection

BACKGROUND: The role of Helicobacter pylori in the pathogenesis and evolution of gastro-oesophageal reflux disease is still debated. AIM: To investigate the impact of Helicobacter pylori infection on the oesophageal function and on intra-gastric and intra-oesophageal pH in patients with gastro-oesophageal reflux. METHODS: Fifty patients with non-complicated-gastro-oesophageal reflux disease classified according to Savary-Miller in: grade O, n=24; grade 1, n=19; grade 2, n=6; grade 3, n=1. Of these patients, 24 were Helicobacter pylori positive and 26 negative. Patients underwent, on two different days, stationary oesophageal manometry and 24-hour gastro-oesophageal pH-metry. RESULTS: No difference was observed between Helicobacter pylori infected and non-infected individuals with regard to lower oesophageal sphincter function, oesophageal peristalsis and gastrooesophageal reflux. These parameters were more impaired in individuals with erosive gastro-oesophageal reflux disease but this result was not dependent on the Helicobacter pylori status. Helicobacter pylori did not influence the pattern of gastric pH; however, considering only individuals with non-erosive gastro-oesophageal reflux disease, gastric pH was significantly higher in infected individuals, who, histologically, also showed a corpus predominant gastritis. CONCLUSIONS: In patients with gastro-oesophageal reflux disease, Helicobacter pylori does not affect the oesophageal motility or the gastro-oesophageal reflux. These parameters are strictly related to the severity of gastro-oesophageal reflux disease as assessed at endoscopy. In patients with non-erosive gastro-oesophageal reflux disease, a corpus predominant Helicobacter pylori gastritis could be responsible for the less severe gastro-oesophageal reflux.     

Recent views on the pathogenesis of gastro-oesophageal reflux disease

The pathogenesis of GORD depends on a mix of factors which vary amongst individual patients. The central issue in the pathogenesis of gastro-oesophageal reflux is understanding of the mechanisms that lead to reflux, since the effects of all other factors depend on this event. Consequently, new information and views about the mechanisms of gastro-oesophageal reflux have been presented in detail. This information suggests that defective lower oesophageal sphincter motility is the most important abnormality that underlies pathological gastro-oesophageal reflux. Two major forms of LOS dysfunction have been identified as responsible for pathological gastro-oesophageal reflux in the horizontal position: (1) an excessively frequent rate of occurrence of transient LOS relaxations; and (2) defective basal LOS tone. Both of these dysfunctions appear to arise from abnormal neural control of the LOS, probably by the central nervous system. The effect of these LOS dysfunctions on gastro-oesophageal competence is probably significantly influenced by non-sphincteric factors, the most important of these apparently being hiatus hernia. Though there is currently poor understanding about the ways in which hiatus hernia impairs gastro-oesophageal competence, measurement techniques have now advanced sufficiently to allow significant accrual of knowledge in this field. Once reflux has occurred, the efficiency of oesophageal acid clearance plays a major role in determining the impact of reflux on the oesophageal mucosa. Recent studies have shown that oesophageal acid clearance depends on both effective volume clearance and neutralization by saliva of residual acid in the oesophageal lumen. The efficiency of oesophageal volume clearance of both stimulated and real reflux has not been studied formally in GORD patients, but the high incidence of peristaltic dysfunction in reflux disease suggests that volume clearance will be defective in some patients. The limited information available about salivation in GORD patients suggests that salivary secretion is no different from that of age-matched controls, but that there is an age-dependent loss of the salivary response to oesophageal acidification. This impairment of salivary response may produce an age-dependent decline of the efficiency of oesophageal acid clearance. Unusually aggressive refluxate and impaired mucosal resistance to injury have been proposed as significant variables which contribute to pathogenesis of reflux disease. The evidence for these factors is circumstantial and scanty. Their importance has probably been overestimated.(ABSTRACT TRUNCATED AT 400 WORDS)     

New approaches to enhance the accuracy of the diagnosis of reflux disease

The accuracy of symptoms in diagnosing gastro-oesophageal reflux disease (GORD) is complicated by the lack of a gold standard test. Statistical techniques such as latent class and Bayesian analyses can estimate accuracy of symptoms without a gold standard. Both techniques require three independent diagnostic tests. Latent class analysis makes no assumptions about the performance of the tests. Bayesian analysis is useful when the accuracy of the other tests is known. These statistical techniques should be used in the future to validate GORD symptom questionnaires comparing them with endoscopy, oesophageal pH monitoring, and response to proton pump inhibitor therapy. Studies that evaluate GORD symptoms are usually done in secondary care. The prevalence of GORD in primary care will be lower and this reduces the positive predictive value of symptoms. There will be some bias in the type of patient referred for diagnosis and this usually decreases the specificity of symptom diagnosis.     

Effects of dietary nitrate on oesophageal motor function and gastro-oesophageal acid exposure in healthy volunteers and reflux patients

BACKGROUND/AIMS: High concentrations of nitric oxide (NO), derived from dietary nitrite in an acid environment, have been demonstrated in the gastric fundus and in the oesophagus. The aim of this study was to investigate whether luminal NO can influence oesophageal smooth muscle performance, lower oesophageal sphincter (LOS) function or gastric and oesophageal acid exposure. METHODS: Eleven healthy volunteers and 9 patients with chronic gastro-oesophageal reflux disease (GORD) received a diet deprived of nitrate/nitrite but supplemented with placebo or potassium nitrate for 4 days in a randomised order. On day 4 in each trial period, manometry was performed including a sleeve sensor registration of the LOS followed by a simultaneous 24-hour intra-gastric and oesophageal pH registration. RESULTS: Nitrate supplementation increased the proportion of effective peristalsis when analysed for the entire study population. No other significant effects of dietary nitrate were found on oesophageal motor variables, on the sphincter resting tone or on the number or duration of transient sphincter relaxations. No effect was found on either gastric acidity or gastro-oesophageal reflux variables. Major reflux symptoms were not influenced by nitrate administration. CONCLUSION: Dietary nitrate did not significantly affect oesophageal motor or LOS function, gastro-oesophageal acid reflux or reflux symptomatology either in healthy volunteers or in GORD patients.     

The role of delayed gastric emptying and impaired oesophageal body motility

Delayed gastric emptying in a variable proportion of patients with gastro-oesophageal reflux disease has been observed in most series, however a relationship between delayed gastric emptying and increased gastro-oesophageal reflux has not been convincingly demonstrated. Enhanced postprandial accommodation and delayed emptying of the proximal stomach have been described, but some controversy exists. Impaired primary peristalsis is often present especially in patients with oesophagitis and its prevalence increases with increasing severity of inflammatory mucosal lesions. Patients with gastro-oesophageal reflux disease often have defective triggering of secondary peristalsis independently of presence of oesophagitis. It is presently unclear if impaired oesophageal motility is a primary defect or an irreversible consequence of inflammation. Attempts at pharmacological improvement of impaired oesophageal motility have been so far disappointing. Patients with partially preserved neuromuscular structures need to be identified in order to select them for new prokinetic therapy.     

Combined multichannel intraluminal impedance and pH monitoring is helpful in managing children with suspected gastro-oesophageal reflux disease

BackgroundGastro-oesophageal reflux is very common in the paediatric age group. There is no single and reliable test to distinguish between physiologic and pathological gastro-oesophageal reflux, and this lack of clear distinction between disease and normal can have a negative impact on the management of children.AimsTo evaluate the usefulness of 24-h oesophageal pH-impedance study in infants and children with suspected gastro-oesophageal reflux disease.MethodsPatients were classified by age groups (A–C) and reflux-related symptoms (typical and atypical). All underwent pH-impedance study. If the latter suggested an abnormal reflux, patients received therapy in accordance with NASPGHAN/ESPGHAN recommendations, while those with normal study had an additional diagnostic work-up. The efficacy of therapy was evaluated with a specific standardized questionnaire for different ages.ResultsThe study was abnormal in 203/428 patients (47%) while normal in 225/428 (53%). Of those with abnormal study, 109 exhibited typical symptoms (54%), and 94 atypical (46%). The great majority of the patients with abnormal study were responsive to medical anti-reflux therapy.ConclusionsWe confirm the utility of prolonged oesophageal pH-impedance study in detecting gastro-oesophageal reflux disease in children and in guiding therapy. Performing oesophageal pH-impedance monitoring in children with suspected gastro-oesophageal reflux disease is helpful to establish the diagnosis and avoid unnecessary therapy.     

Diagnosis and management of patients with reflux symptoms refractory to proton pump inhibitors

Approximately a third of patients with suspected gastro-oesophageal reflux disease are resistant or partial responders to proton pump inhibitors (PPIs). Many of these patients do not have gastro-oesophageal reflux disease, but suffer from functional heartburn or dyspepsia. The potential mechanisms underlying failure of PPI treatment in patients with reflux-related symptoms include persistence of isolated or mixed acid, weakly acidic, bile or gas reflux, impaired oesophageal mucosal integrity, chemical or mechanical hypersensitivity to refluxates and psychological comorbidity. After thorough clinical evaluation and failure of empirical changes in PPI dose regime, diagnostic investigations include endoscopy and reflux monitoring with pH or pH-impedance monitoring. If symptoms are clearly related to persistent reflux, baclofen, antireflux surgery or pain modulators can be considered. If not, pain modulators are the only currently available therapy.     

Intra-oesophageal acid suppression in complicated gastro-oesophageal reflux disease: esomeprazole versus lansoprazole

BACKGROUND: Acid suppression is the mainstay of therapy in gastro-oesophageal reflux disease. Esomeprazole 40 mg is more effective than lansoprazole 30 mg in healing mucosal lesions in severe erosive reflux oesophagitis. However, data comparing esomeprazole with lansoprazole in patients with complications of gastro-oesophageal reflux disease, such as ulcerative reflux oesophagitis and Barrett's oesophagus, are lacking. AIM: To compare the efficacy of esomeprazole and lansoprazole at their standard dosages in suppressing oesophageal acid exposure in complicated gastro-oesophageal reflux disease. METHODS: Thirty patients with complicated gastro-oesophageal reflux disease (7 with ulcerative reflux oesophagitis and 23 with Barrett's oesophagus), randomly assigned to receive 40 mg esomeprazole (n=16) or 30 mg lansoprazole (n=14) once daily, underwent oesophageal 24-h pH monitoring while on therapy. Total, upright diurnal and supine nocturnal percentage acid reflux time were assessed. RESULTS: Esomeprazole was significantly more effective than lansoprazole in decreasing oesophageal acid exposure. Normalisation of both total and supine nocturnal percentage acid reflux time was obtained in 12 of 16 (75%) patients treated with esomeprazole but only in 4 of 14 (28%) cases treated with lansoprazole (p=0.026). CONCLUSIONS: Normalisation of oesophageal acid exposure can be achieved in the majority of complicated gastro-oesophageal reflux disease cases with esomeprazole 40 mg once daily.     

Oesophageal function in patients with angina pectoris: a comparison of patients with normal coronary angiograms and patients with coronary artery disease

Oesophageal function was assessed in 52 patients with angina pectoris whose coronary angiograms were completely normal and in 21 patients with angina pectoris who had significant coronary artery disease. During a standard oesophageal manometric study, abnormalities were found in 23 (44%) patients with normal coronary angiograms but in only 2 (10%) patients with coronary artery disease (p less than 0.01). Twenty-four (46%) patients with normal coronary angiograms were found to have gastro-oesophageal reflux disease during 24-hour oesophageal pH monitoring. Of the 52 patients with normal coronary angiograms, 19 (37%) had gastro-oesophageal reflux disease and abnormal oesophageal motility, 5 (10%) had gastro-oesophageal reflux disease alone, and 7 (13%) had oesophageal motility disorder alone. The use of provocation procedures, including intravenous edrophonium during oesophageal manometry and treadmill exercise testing during pH monitoring, enabled the oesophageal abnormality to be demonstrated simultaneously with chest pain in 25 of these 31 patients. Typical angina pectoris, coincident with abnormal oesophageal motility, was precipitated in a subgroup of patients who had been shown to have oesophageal manometric abnormalities and gastro-oesophageal reflux disease by the infusion of hydrochloric acid into the oesophagus; both the chest pain and manometric abnormality resolved following the oral administration of antacid.     

Gastric dysrhythmias occur in gastro-oesophageal reflux disease complicated by food regurgitation but not in uncomplicated reflux

AIM: To investigate gastric pacemaker activity in gastro-oesophageal reflux disease using the electrogastrogram. PATIENTS: Forty patients with gastro-oesophageal reflux disease (20 with acid reflux, 20 with the additional symptom of food regurgitation) and 30 asymptomatic controls. METHODS: Patients were studied using an electrogastrogram, oesophageal manometry, and 24 hour ambulatory oesophageal pH analysis. RESULTS: An abnormal electrogastrogram was recorded in two (7%) controls, two (10%) patients with acid reflux, and 10 (50%) patients with food regurgitation. Food regurgitators had significantly more gastric dysrhythmias (tachygastrias) both before (p<0.02) and after (p<0.01) a test meal. Gastric pacemaker activity was also significantly less stable following the test meal in food regurgitators (p<0.003). Patients with food regurgitation and an abnormal electrogastrogram had higher oesophageal acid exposure than those with a normal electrogastrogram (p<0.05). CONCLUSIONS: The electrogastrogram is usually normal in gastro-oesophageal reflux disease but an abnormal rhythm occurred in half of our patients with the additional symptom of food regurgitation. Furthermore, an abnormal electrogastrogram is associated with increased oesophageal acid exposure.     

Relations among autonomic nerve dysfunction, oesophageal motility, and gastric emptying in gastro-oesophageal reflux disease.

Recent studies suggest that vagal nerve dysfunction may be important in the aetiology of gastro-oesophageal reflux disease. Delayed oesophageal transit and slowed gastric emptying occur frequently and may also be of pathogenic importance. In 48 patients with gastro-oesophageal reflux disease we studied the prevalence of and relations between autonomic nerve dysfunction (as assessed by cardiovascular reflex tests) and oesophageal transit, oesophageal motility, gastric emptying, and endoscopic grade of oesophagitis. Of the 48 patients, 21 (44%) had abnormal autonomic nerve function, which was predominantly parasympathetic. Oesophageal transit was delayed in 28% of the patients and gastric emptying of the solid component of the meal was delayed in 46%. Oesophageal transit was significantly (p less than 0.007) slower in patients with abnormal autonomic nerve function. The percentage of synchronous oesophageal contractions was related to the score for autonomic nerve dysfunction (r = 0.40, p less than 0.05). There was no significant relation of autonomic nerve dysfunction to either delayed gastric emptying or endoscopic grade of oesophagitis. We conclude that in gastro-oesophageal reflux disease there is a high prevalence of parasympathetic nerve dysfunction which relates to delayed oesophageal transit and abnormal peristalsis and may therefore be of pathogenic importance.     

Inflammation at the cardio-oesophageal junction: relationship to acid and bile exposure

BACKGROUND: The aetiology of inflammation in cardiac mucosa at the gastro-oesophageal junction (carditis) is unclear, although gastro-oesophageal reflux has been suggested. OBJECTIVES: To correlate histological features of carditis with oesophageal acid exposure (gastro-oesophageal reflux) and proximal gastric bile exposure (duodenogastric reflux) in patients with symptoms of gastro-oesophageal reflux disease (GORD). METHODS: Sixty-six patients with reflux symptoms underwent endoscopy with biopsy, oesophageal manometry, 24-h oesophageal pH testing and 24-h proximal gastric Bilitec 2000 testing. Inflammation in glandular mucosa was assessed using the updated Sydney System. Fifteen healthy volunteers underwent pH and Bilitec 2000 testing and served as controls. RESULTS: There was no correlation between either the presence or histological grade of carditis and oesophageal acid exposure or proximal gastric bilirubin exposure. Patients with reflux symptoms had as much duodenogastric reflux into the proximal stomach as did control subjects. CONCLUSIONS: We were unable to establish either gastro-oesophageal or duodenogastric reflux as the predominant cause of inflammation in cardiac mucosa.     

Pathophysiological characteristics of the various forms of gastro-oesophageal reflux disease: Spectrum disease or distinct phenotypic presentations?

BACKGROUND: The traditional approach to gastro-oesophageal reflux disease as a spectrum disease has recently been criticised and the distinct phenotypic presentations model has been proposed. AIM: To evaluate the main pathophysiological characteristics of various gastro-oesophageal reflux disease presentations. METHODS: Oesophageal manometry and 24-h pH-monitoring were performed in a gastro-oesophageal reflux disease series collected in a 7-year period. RESULTS: Four hundred and twenty-one subjects were studied. Mean total percentage acid reflux time was significantly higher in long-segment Barrett's oesophagus and in ulcerative oesophagitis than in all the other gastro-oesophageal reflux disease groups, whilst in short-segment Barrett's oesophagus results were quite similar to those found in non-erosive reflux disease and in erosive reflux disease. Patients with ulcerative oesophagitis and long-segment Barrett's oesophagus were older than all the other gastro-oesophageal reflux disease groups. The mean lower oesophageal sphincter pressure was significantly reduced in non-erosive reflux disease, erosive reflux disease, ulcerative oesophagitis, short-segment Barrett's oesophagus and long-segment Barrett's oesophagus as compared with functional heartburn and hypersensitive oesophagus and with controls. CONCLUSIONS: In keeping with the spectrum model of gastro-oesophageal reflux disease, severity of acid reflux increases from non-erosive reflux disease through erosive reflux disease up to ulcerative oesophagitis and long-segment Barrett's oesophagus. Ulcerative oesophagitis and long-segment Barrett's oesophagus could represent an advanced step in the natural history of gastro-oesophageal reflux disease. Our results do not confirm the distinct phenotypic presentations hypothesis.     

Treatment of gastro-oesophageal reflux disease through control of transient lower oesophageal sphincter relaxations - feasibility, practicality and possibilities

Current treatment of gastro-oesophageal reflux disease (GORD) has, in certain respects arisen empirically. The early recognition that oesophageal symptoms and oesophagitis were the result of the damaging effects of gastric acid¹ focused attention initially on acid neutralisation and, more recently, on acid suppression as approaches to the pharmacological therapy of reflux disease. However, although the major manifestations of reflux disease are a result of oesophageal acid exposure, reflux disease is primarily a disorder of oesophageal motor function in which defective control of the gastro-oesophageal barrier leads to the escape of gastric contents into the oesophagus². Improved control of oesophageal motility, especially patterns of lower oesophageal sphincter (LOS) function that lead to reflux, is a physiologically direct and attractive approach to the treatment of reflux disease as it addresses the fundamental aspects of its pathophysiology.     

Reliability of 24-hour oesophageal pH monitoring under standardized conditions

BACKGROUND: Twenty-four-hour pH monitoring is an investigation technique that can give both false-positive and false-negative results, depending on patient factors such as diet and different activities. The aim was to study the reproducibility of 24-h oesophageal pH monitoring under as standardized conditions as possible in patients with symptoms of gastro-oesophageal reflux disease. METHODS: Antimony pH electrodes were used in 22 adult patients who were investigated twice, 6 weeks apart, under identical conditions. They were hospitalized and were served a standardized diet which had been tested to contain no lower than pH 5.0. Neither coffee nor smoking was allowed. The patients had to refrain from proton-pump inhibitors for 10 days and H2 blockers for 2 days prior to the investigation. The paired t test was used. RESULTS: There was no significant difference in total reflux time, upright or supine reflux time, or longest reflux periods between the two test occasions. However, there were discordant results in six patients who had normal total reflux time on one test occasion but pathological results on the other. CONCLUSION: Since the biological variability of gastro-oesophageal reflux is not negligible from time to time, a normal 24-h oesophageal pH test should be assessed with caution.     

Reliability of 24-Hour Oesophageal pH Monitoring Under Standardized Conditions

Background : Twenty-four-hour pH monitoring is an investigation technique that can give both false-positive and false-negative results, depending on patient factors such as diet and different activities. The aim was to study the reproducibility of 24-h oesophageal pH monitoring under as standardized conditions as possible in patients with symptoms of gastro-oesophageal reflux disease. Methods : Antimony pH electrodes were used in 22 adult patients who were investigated twice, 6 weeks apart, under identical conditions. They were hospitalized and were served a standardized diet which had been tested to contain no lower than pH 5.0. Neither coffee nor smoking was allowed. The patients had to refrain from proton-pump inhibitors for 10 days and H 2 blockers for 2 days prior to the investigation. The paired t test was used. Results : There was no significant difference in total reflux time, upright or supine reflux time, or longest reflux periods between the two test occasions. However, there were discordant results in six patients who had normal total reflux time on one test occasion but pathological results on the other. Conclusion : Since the biological variability of gastro-oesophageal reflux is not negligible from time to time, a normal 24-h oesophageal pH test should be assessed with caution.