Efficacy of esomeprazole in controlling reflux symptoms, intraesophageal, and intragastric pH in patients with Barrett's esophagus.

Barrett's esophagus is a metaplastic condition associated with gastroesophageal reflux disease and an increased risk for adenocarcinoma. Acid plays a significant role in the development and progression of Barrett's esophagus and high dose proton pump inhibitor (PPI) therapy is often needed. The aim of this study is to assess the efficacy of esomeprazole, a new potent PPI, on symptom relief and intraesophageal and intragastric acid suppression in patients with Barrett's esophagus (BE). Patients were evaluated by standardized questionnaires and dual sensor 24-h pH monitoring while receiving esomeprazole at a dose (40-80 mg/day) needed for control of symptoms. Analyses of intraesophageal and intragastric pH profiles were then made. Thirteen patients, mostly men, were studied. All tolerated esomeprazole (40-80 mg/day) with good symptom control. Sixty-two percent of patients with BE had abnormal intraesophageal pH profiles despite adequate symptom control on esomeprazole which was associated with significant breakthrough of intraesophageal acid control, particularly at night. Low nocturnal intragastric pH correlated highly with nocturnal intraesophageal acid reflux (P = 0.004) and there was a relative failure of nocturnal intragastric acid control with esomeprazole. A high percentage of patients with BE continue to exhibit pathologic GERD and low intragastric pH despite esomeprazole for reflux symptom control. For an antisecretory treatment aimed at chemoprevention of esophageal adenocarcinoma to be effective, higher PPI dosing confirmed by pH monitoring may be necessary.     

Effect of nizatidine 300 mg at night and omeprazole 20 mg in the morning on 24-hour intragastric pH and bacterial overgrowth in patients with acute duodenal ulcer

The study investigated the effect of either nocturnal acid suppression by the H₂ antagonist nizatidine 300 mg at night or prolonged acid suppression by the proton-pump inhibitor omeprazole 20 mg in the morning, during four weeks, on intragastric pH profile, occurrence of bacterial growth in gastric fluid and biopsies, and healing rate in 23 patients with an acute duodenal ulcer. The endoscopic healing rate did not differ significantly between the two treatment modalities. The 24-hr acid secretion was significantly more reduced by omeprazole than nizatidine (P<0.002). After treatment by nizatidine and omeprazole, respectively, median 24-hr intragastric pH increased from 1.5 to 1.8 (P<0.01) and from 1.5 to 6.1 (P<0.01), respectively. Nighttime acid inhibition did not differ significantly. The difference in gastric bacterial colonization after either omeprazole or nizatidine did not reach significance. However, median 24-hr pH and the fraction of the day with pH<3 and pH<4 were significantly correlated to bacterial colonization of the gastric fluid (P<0.05).This study was supported by Eli Lilly Nederland B.V.     

Stomach myoelectrical response of patients with gastroesophageal reflux disease receiving omeprazole treatment

BACKGROUND AND AIM: Proton pump inhibitor treatment is effective for gastroesophageal reflux disease (GERD). It is unknown whether these agents effect any change in the stomach myoelectricity of GERD patients. Electrogastrographic (EGG) recording was used to study the probable effect of omeprazole on GERD patients. METHODS: Nineteen endoscopically confirmed GERD patients and 38 dyspepsia-free controls were invited to receive EGG recording. After daily omeprazole treatment for 4 weeks, the symptomatic response of GERD patients was scaled, healing of erosive esophagitis was endoscopically assessed, and EGG recording was repeated for comparison. RESULTS: Before treatment, GERD patients and controls displayed similar dominant frequency, whereas the former had higher dominant power compared with controls, either in fasting (29.2 +/- 6.0 dB compared with 25.3 +/- 3.8 dB, P < 0.01) or postprandial (31.9 +/- 5.6 dB compared with 27.7 +/- 3.8 dB, P < 0.001) recording. They also had diminished percentile normal rhythm (2-4 c.p.m.), irrespective of fasting (40.2 +/- 14.5% compared with 65.8% +/- 23.5%, P < 0.001) or postprandial (47.5 +/- 23.3% compared with 77.9 +/- 16.8%, P < 0.001) recording. After omeprazole treatment, healing was achieved in 12 patients (63.2%). Among the abnormal EGG parameters, only the postprandial percentile normal rhythm was restored (47.5 +/- 23.3% compared with 65.2 +/- 20.8%, P < 0.01). CONCLUSIONS: Gastroesophageal reflux disease patients may have obvious dysrhythmia and higher myoelectrical power. Effective omeprazole treatment only improves the postprandial myoelectrical regularity, whereas abnormal EGG parameters remain impaired.     

Comparison of stationary vs ambulatory 24-hour pH monitoring systems in diagnosis og gastroesophageal reflux disease

Twenty-four-hour intraesophageal pH monitoring is presently considered the most reliable diagnostic test for gastroesophageal reflux. Prolonged esophageal pH measurements can be obtained in hospitalized patients with a stationary technique and in ambulant outpatients by means of a portable device; however, there have been no studies that have examined whether the two approaches provide a similar diagnostic accuracy. We performed a prospective study to compare stationary and ambulatory pH-metry in the diagnosis of gastroesophageal reflux. Seventy-seven control subjects and 178 patients with proven gastroesophageal reflux disease were randomized to either ambulant or static pH-metry, which was performed with standard pH electrodes, sensors, and recorders. Reflux events (intraesophageal pH<4.0) analyzed were: number of episodes; total, upright, and supine reflux time; number of episodes lasting >5 min; and duration of the longest episode. A composite score of all reflux events according to DeMeester was also calculated. The limits of normality were defined as the 95th percentiles of the control groups. Both controls and patients assigned to either pH monitoring method were comparable. Of 255 studies attempted, 243 (95%) were completed successfully. The results showed similar median values of reflux events for the two control groups and for the two patients groups. Percent total reflux time provided a good separation between normal and abnormal reflux, with a sensitivity of 0.92 for static pH-metry and 0.68 for the ambulant procedure (respective 95th percentiles, 3.4 and 4.6). The lower sensitivity of ambulatory pH-metry compared to the stationary method could not be attributed to the higher normal limit in the former; circumstantial evidence suggests that dietary restrictions by the patients to minimize symptoms during home monitoring were probably responsible of this relatively high false negative rate. In conclusion, the results confirm the accuracy of stationary pH monitoring in the diagnosis of gastroesophageal reflux and show that the ambulatory procedure is less reliable; its sensitivity could probably be improved by strict dietary standardization.Supported in part by grants 87/1132, 89/631 and 90/505 from FISSS, Spanish Ministry of Health.A preliminary communication of this work was presented at the 3rd International Polydisciplinary Congress of the OESO, Paris, June 1990.     

High-dose esomeprazole is required for intraesophageal acid control in gastroesophageal reflux disease patients with hiatus hernia

Background and Aim: The aim of this study was to assess whether the efficacy of proton pump inhibitors (PPI) therapy at a standard dose in esophageal acid control is affected by the presence of hiatus hernia in Chinese gastroesophageal reflux disease patients, and whether a higher dose of PPI is required for acid control. Methods: Consecutive gastroesophageal reflux disease patients who had typical reflux symptoms and abnormal baseline 24‐h esophageal pH and underwent upper endoscopy were enrolled to receive esomeprazole at 40 mg once daily for 4 weeks. Patients underwent the dual‐channel 24‐h pH test at the end of 4‐week therapy. If the 24‐h esophageal pH was still abnormal at the end of 4‐week therapy, then esomeprazole at 40 mg twice daily was given for another 4 weeks after a washout interval of 1 week, and a 24‐h pH test was repeated at the end of the therapy. Results: Overall, 76 patients were included, 13 with hiatus hernia. Of the 76 patients treated with a 40 mg of esomeprazole daily, esophageal acid exposure was normalized in 64 (84.2%). Normalization of acid exposure was achieved by standard PPI therapy in 53.2% (7/13) of patients with hiatus hernia and 90.5% (57/63) of those without (P = 0.004). A double dose of esomeprazole was successful in normalizing the esophageal pH in all 12 non‐responders to the standard dose of esomeprazole, including the six patients with hiatus hernia and six patients without. Conclusions: The standard‐dose of esomeprazole fails to normalize the esophageal pH in almost 50% of patients with hiatus hernia, in whom the “double‐dose” esomeprazole therapy is required.     

Comparison of omeprazole and ranitidine in treatment of refractory gastroesophageal reflux disease in patients with gastric acid hypersecretion

Secretion of gastric acid and volume, serum gastrin concentration, and ambulatory 24-hr esophageal pH monitoring were evaluated prospectively in 12 patients with idiopathic gastric acid hypersecretion (basal acid output greater than 10.0 meq/hr) undergoing treatment for refractory chronic long-standing pyrosis. Treatment lasted six months and consisted of three months of ranitidine (mean 2150 mg/day, range 1200–3000 mg/day), followed by three months of omeprazole (mean 33 mg/day, range 20–60 mg/day). Both ranitidine and omeprazole significantly reduced gastric acid output (P<0.001) and gastric volume output (P<0.001) compared to a basal evaluation and resulted in complete disappearance of pyrosis. Total reflux time (percent 24 hr intraesophageal pH less than 4) was significantly reduced by ranitidine (P<0.02) and omeprazole (P<0.001) compared to basal evaluation; however, the effects of omeprazole were significantly greater than ranitidine (P<0.05). Omeprazole caused a significant increase in serum gastrin concentration compared to both basal and ranitidine (P<0.05). Endoscopically documented erosive esophagitis was present in nine of the 12 patients, and seven of the 12 patients had Barrett's epithelium. All 12 patients had complete resolution of pyrosis and healed esophagitis by six months, but no significant endoscopic regression was observed in the extent of Barrett's epithelium. No side effects occurred with these high doses of ranitidine or omeprazole. These results indicate that high-dose ranitidine and omeprazole are effective therapy for refractory gastroesophageal reflux disease. However, with omeprazole, total reflux times are reduced more than with ranitidine, often into the normal range. That marked reduction of gastric acid secretion with omeprazole, which greatly reduces total reflux times, accounts for the significant elevation of serum gastrin concentration seen during omeprazole therapy.     

含餐8 h食管pH监测与常规24 h pH监测对胃食管反流病的诊断价值比较

目的探讨含餐8h食管pH监测对胃食管反流病(GERD)的诊断意义,并以常规24hpH监测为标准验证其灵敏度及特异度。方法对2003年3月至2006年9月北京大学人民医院消化科221例患者进行食管测压和pH监测。首先由系统计算24h DeMeester积分,≥14.72分诊断为胃食管反流病。入选患者晚餐开始共计8h的监测数据,同样计算DeMeester积分,相同的标准诊断胃食管反流病。比较两种方法的一致性及积分的相关性。结果221例患者经常规24hpH监测诊断胃食管反流病124例,正常97例,含餐8hpH监测方法诊断胃食管反流病120例,正常101例。含餐8h的灵敏度为93.5%,特异度95.9%,经Kappa及Mc-nemar检验2种方法具有良好的一致性,部分结果的差异不具有显著性。2种检测方式DeMeester积分的相关系数为0.929。结论含餐8小时监测法和24hpH监测法具有良好的一致性,有望用于GERD特别是内镜阴性GERD的诊断。     

Reliability of 24-hour home esophageal ph monitoring in diagnosis of gastroesophageal reflux

Twenty-four-hour home esophageal pH monitoring is proposed in order to study gastroesophageal reflux (GER) so that prolonged use of costly hospital equipment and staff can be curtailed and the diagnostic accuracy of the examination improved. Eighty-six patients affected by GER symptoms and 20 healthy volunteers underwent 24-hr home esophageal pH monitoring, x-rays, and endoscopy of the upper gastrointestinal tract to investigate reliability of outpatient recording. Fifteen more patients consecutively underwent out- and inpatient recording to detect possible differences between these methods in the two daily periods. Outpatient monitoring was well tolerated in 94.7% of the patients; 14.3% of them markedly reduced their routine activities. The range of normality of outpatient recording does not differ from that of inpatients. In the 15 patients who consecutively underwent out-and inpatient monitoring, no significant differences were reported. The sensitivity of 24-hr home esophageal pH recording is 0.85, the specificity 1, the accuracy for negative prediction 0.68, and the accuracy for positive prediction 1. The reliability of 24-hr home esophageal pH monitoring is comparable to inpatient recording. It allows hospital cost reduction and is also better tolerated by patients but has not greatly improved the diagnostic accuracy of the gastroesophageal reflux pH monitoring.Supported by the Ministere Pubblica Istruzione, Rome; and Finanziamenti per studi e ricerche 40%, Com. 06, Cat 12-07 imp. 11515, University of Bologna.     

Impact of 24-h esophageal pH monitoring on the diagnosis of gastroesophageal reflux disease: defining the gold standard

BACKGROUND AND AIMS: The tests that are currently available for the diagnosis of gastroesophageal reflux disease (GERD) lack the desired diagnostic accuracy. To date, only pH monitoring has been shown to have a good sensitivity and specificity, but recent studies have failed to confirm this. Thus there is a need to find a test with acceptable sensitivity and specificity for diagnosing GERD. The present study aimed to find a single test or a combination of tests that could serve as a gold standard for the diagnosis of GERD and to identify an evidence-based diagnostic work-up for GERD in clinical and research settings. METHODS: A prospectively conducted masked study was carried out in which 109 GERD patients were recruited on the basis of symptom score evaluation (heartburn and/or regurgitation). After informed consent was given, the patients underwent various tests, including esophagogastroduodenoscopy with biopsy from the lower esophageal mucosa during the first visit, followed by omeprazole challenge test (OCT), radionuclide scintigraphy, barium swallow and finally 24-h esophageal pH monitoring. A positive concordance of three or more tests was taken as the gold standard. RESULTS: The results of all six tests were available for 70 patients. As a single diagnostic test, pH testing had the best combination of sensitivity and specificity (Youden's J = 0.69). Even in cases of endoscopy-negative reflux disease, pH monitoring was the most sensitive and specific test (93.3% and 90.4%, respectively; J = 0.83). OCT, endoscopy and histopathology also had good sensitivity (84.4%, 64.4%, 82.2%, respectively). A combination of OCT, endoscopy and histopathology achieved a sensitivity of 100%. CONCLUSIONS: A combination of OCT, endoscopy and histology will identify all cases of GERD. As these investigations are easily available, they should form the diagnostic work-up in clinical situations. 24-h esophageal pH testing, despite being the gold standard, has no utility in routine clinical settings and hence its availability should be limited to tertiary care settings.     

Correlation of 24-hr esophageal pH patterns with clinical features and endoscopy in gastroesophageal reflux disease

We performed 24-hr ambulatory esophageal pH monitoring in north Indian patients with gastroesophageal reflux disease (GERD) and correlated it with symptom severity and endoscopic abnormalities. Thirty-six consecutive patients with symptomatic GERD and 16 healthy volunteers underwent objective grading of clinical symptoms and endoscopic findings. Total, supine, and upright reflux periods as well as frequency and duration of reflux episodes were determined from the 24-hr pH-metry record using standard software. This was abnormal in 32 patients, who could be categorized into upright refluxers (31.2%), supine refluxers (34.4%), and combined refluxers (34.4%). Supine reflux and upright reflux were distinct entities that did not correlate with each other (r=0.22,P=NS). In upright refluxers, symptoms (P<0.02) and=" endoscopic=" abnormalities=">P<0.005) were=" milder=" than=" in=" combined=" refluxers.=" total=" duration=" of=" acid=" exposure=" correlated=" significantly=" with=" severity=" of=" symptoms=">P<0.001) and=" endoscopic=" esophagitis=">P<0.005). patients=" with=" gerd=" had=" three=" distinct=" patterns=" of=" abnormal=" gastroesophageal=" reflux,=" with=" upright=" refluxers=" having=" milder=" disease=" and=" supine=" and=" combined=" refluxers=" having=" more=" severe=" disease.=" this=" may=" reflect=" differences=" in=" underlying=" mechanisms=" of=">     

24h动态PH监测在支气管哮喘合并胃食管反流病的临床研究

目的探讨24 h动态PH监测在支气管哮喘合并胃食管反流病(GERD)的诊断价值。方法纳入支气管哮喘患者32例(A组),GERD患者40例(B组),支气管哮喘合并GERD患者32例(C组),对3组患者行24 h食管p H监测,记录胃酸反流的总次数,总计、立位、卧位p H4的百分比,并行食管测压。结果C组及B组近段、中段远端的食管体部压力低于A组;A组食管括约肌静息压力、蠕动波传导速度高于C组及B组,反流频数C组低于其他两组;A组酸反流总次数,总计、立位、卧位p H4的百分比和De Meester评分均少于C组及B组。结论 24 h动态PH监测能发现更多的反流时间,卧位p H4百分比及反流频数是重要的参考指标。     

Effect of intravenous omeprazole on intragastric pH during intravenous infusion of amino acids

Intravenous amino acids stimulate gastric acid secretion by an unknown mechanism. In patients on parenteral nutrition, this amino acid-induced gastric acid secretion might contribute to the failure of H₂-receptor antagonists to raise intragastric pH above 4.0, a level thought to be needed to prevent stress ulceration. Therefore we studied the effect of single and repeated doses of the H⁺/K⁺-ATPase blocker omeprazole on the intragastric pH during a 3-hr infusion of amino acids in 10 healthy volunteers; 5% glucose was used as a control infusion. Amino acids significantly decreased intragastric pH when compared to glucose infusion (P <0.05). After intravenous administration of 40 mg, 80 mg and 2 × 40 mg omeprazole, this amino acid-induced fall in pH was significantly inhibited (P < 0.01). No advantage of the 80-mg dose over the 40-mg dose could be demonstrated. The repeated dose of 40 mg showed a tendency to higher pH values compared to the single-dose experiments, which reached significance in the amino acid experiments only (P <0.05). Neither during the infusion of amino acids nor the glucose infusion omeprazole was able to continuously raise intragastric pH above 4.0. In conclusion, this study shows that intravenous omeprazole prevents gastric acid stimulation by intravenous amino acids but fails to continuously raise intragastric pH above 4.     

Exclusion of meal periods from ambulatory 24-hour pH monitoring May improve diagnosis of esophageal acid reflux

Distal esophageal pH less than 4 is frequently seen during meal ingestion in 24-hr ambulatory pH monitoring for the diagnosis of gastroesophageal reflux disease (GERD). The characteristics of this meal-related apparent reflux without diet restriction was evaluated. Data from normal volunteers (N=21) and consecutive patients (N=66) referred with heartburn and/or chest pain were studied with ambulatory pH monitoring. The median percent times pH<4 in the distal esophagus were significantly greater in symptomatic patients than controls for total 24-hr, upright, and supine periods, and postprandial periods of 30, 60, 90, 120, and 150 min (P values of 0.007–0.03). However, the median percent time pH<4 during the meal periods was the same for patients (4.4%) and for controls (6.6%) withP=0.23. Excluding the meal periods from analysis resulted in greater separation between controls and patients with abnormal acid exposure when compared to the conventional method. Patients should maintain their usual routine without diet restriction during 24-hr ambulatory pH studies in the clinical setting. Furthermore, exclusion of meal periods can eliminate meal-time pH variabilities without affecting postprandial acid exposure and improve the diagnosis of GERD.     

Ambulatory 24-hour esophageal pH monitoring

If 24-hour esophageal pH monitoring is to be a useful diagnostic tool, it must reliably discriminate gastroesophageal reflux patients despite daily variations in distal esophageal acid exposure. To address this issue, we studied 53 subjects (14 healthy normals, 14 esophagitis patients, and 25 patients with atypical symptoms) with two ambulatory pH tests performed within 10 days of each other. Intrasubject reproducibility of 12 pH parameters to discriminate the presence of abnormal acid reflux was determined. As a group, the parameters of percent time with pH<4 (total, upright, recumbent) were most reproducible (80%). Therefore, a subject was defined as having gastroesophageal reflux disease if at least one of these three values were abnormal. Intrasubject reproducibility for the diagnosis of reflux disease was 89% for the entire sample. Among subsets, the reproducibility was 93% for the normals and esophagitis patients and 84% for the atypical symptom patients. Total percent time with pH<4 was the single most discriminate pH parameter (85%) and nearly equaled that of the three combined parameters (89%). The intrasubject variability of this parameter was determined by the mean ±2sd of the relative differences between the two test results for all 53 subjects. Total percent time with pH<4 may vary between tests by a factor of 3.2-fold or less (218% higher to 69% lower). We conclude: (1) ambulatory 24-hr esophageal monitoring is a reproducible test for the diagnosis of gastroesophageal reflux disease; and (2) the large intrastudy variability in 24-hr total acid exposure may limit this test's usefulness as a measurement of therapeutic improvement.Supported, in part, by Public Health Services Grant AM 34200-01A1 from NIADDIK.     

Inclusion of supine period in short-duration pH monitoring is essential in diagnosis of gastroesophageal reflux disease

Prolonged esophageal pH monitoring is the most accurate method for detecting abnormal gastroesophageal reflux (GER) in patients with gastroesophageal reflux disease (GERD). However, some investigators have found that short-duration postprandial pH monitoring in the upright position is also useful, while others have failed to find such results. Therefore, we have compared a 6-hr period of pH monitoring (3-hr postprandial period after daytime meal and 3-hr supine period) with a total 24-hr period in detecting abnormal gastroesophageal reflux. Sixty-five patients (44 men, mean age 41.3 years) with GERD and 16 healthy volunteers (11 men, mean age 34.3 years) underwent 24-hr pH monitoring according to a standard protocol. Various reflux parameters during 24-hr pH monitoring were compared with reflux parameters during the 6-hr period. Abnormal GER was detected in 56 patients presenting with typical symptoms of GERD (sensitivity 86.2%). These patients could be further divided into upright (N=18), supine (N=15), and combined (N=23) refluxers, depending on the posture in which abnormal reflux occurred. Esophageal pH monitoring during the 3-hr postprandial upright period showed abnormal reflux in only 35 patients (sensitivity 53.8%;P<0.00005, compared with the 24-hr pH monitoring period). Abnormal GER was identified in 13 of 18 upright, 19 of 23 combined, and only one of 15 supine refluxers, as well as in two of nine patients with normal 24-hr pH-metry. However, inclusion of the 3-hr supine monitoring period in the 3-hr postprandial upright period improved detection of abnormal GER to 78.5% (51 patients;P=NS compared with 24-hr pH monitoring period). This was related mainly to improved detection of abnormal GER in supine refluxers (11 of 15; 73.3%). Esophageal acid exposure time correlated significantly with severity of esophagitis only during the total and supine periods of both the 24- and 6-hr periods and not during the upright period. Esophageal acid clearance correlated significantly with increasing grades of esophagitis for the supine and total periods only. We conclude that 3-hr postprandial pH monitoring, as has been conventionally practiced, is not appropriate in the detection of abnormal GER; inclusion of a supine period in the short-duration pH monitoring schedule increases the detection of pathological reflux. We therefore recommend that a supine period should be included in short-duration pH monitoring schedules. We also found that supine reflux was the most important factor in the development of esophagitis.     

Tolerance to H2 receptor antagonist correlates well with the decline in efficacy against gastroesophageal reflux in patients with gastroesophageal reflux disease

BACKGROUND AND AIM: The attenuated antisecretory activity of H2 receptor antagonists (H2RA) during continuous administration is known as the tolerance phenomenon. The authors recently clarified that presence or absence of Helicobacter pylori infection influences the occurrence of the tolerance phenomenon. The aim of this study was to clarify whether tolerance to H2RA is correlated with attenuation of the inhibitory effect against gastroesophageal acid reflux in patients with gastroesophageal reflux disease (GERD). METHODS: Ten male patients with GERD symptoms and abnormal gastroesophageal reflux were investigated by pH monitoring on days 1 and 15 of continuous oral famotidine administration at 20 mg twice daily, and H. pylori infection was examined using the urea breath test. RESULTS: Intragastric and intraesophageal acidity were significantly decreased on the first day of famotidine administration, but then increased during the 15-day administration period in seven patients who were negative for H. pylori. In contrast, the efficacy of famotidine against gastric acid secretion and gastroesophageal acid reflux was not attenuated in three H. pylori-positive patients. The changes in GERD symptoms were correlated with the change in the degree of gastroesophageal reflux. CONCLUSION: The presence or absence of tolerance to H2RA during 15-day administration is correlated with the efficacy for inhibition of gastroesophageal acid reflux.     

Analysis of the acidity index and integrated intragastric acidity in 645 patients presenting with gastroesophageal reflux disease symptoms

Objective. In a recent study of patients receiving proton-pump inhibitor (PPI) therapy, a new parameter, the acidity index, was described as being less complicated to calculate and of comparable accuracy (r=0.93) to integrated intragastric acidity (IA) in assessing intragastric pH control. The aim of this study was to correlate AI with IA using a large database of ambulatory 24-h pH-metry studies in untreated patients presenting with gastroesophageal reflux disease (GERD) symptoms. Material and methods. We retrospectively analyzed 645 studies obtained from 1995 to 2001. Daytime (0800?h–2200?h), night-time (2200?h–0800?h) and 24-h IA and AI were calculated according to age, gender and the presence or absence of GERD, and correlations between these parameters were assessed using linear regression with F-statistic values, p-values and Akaike's Information Criterion values. GERD was defined as total esophageal pH time <4.0, 5?cm above the lower esophageal sphincter, for ≥4.2% of the day. IA and AI were calculated as follows: IA (mmol.h/l)?=?∑(acid in mmol/l at time “t”?+?acid in mmol/l at time “t???1”)/2×(“t”–“t???1”); AI=(%time pH?Results. Overall, the mean 24-h IA value was 882.0±820.0?mmol.h/l (daytime 392.0±400.0, night-time 490.0±486.0). The mean 24-h AI value was 102.0±87.0 (daytime 86.0±80.0, night-time 120.0±114.0, p<0.001). The mean 24-h IA value was 1057.0±829.4?mmol.h/l (daytime 459.8±406.0, night-time 597.2±500.4, p<0.001) in GERD patients and 713.0±775.0?mmol.h/l (daytime 326.0±383.0, night-time 387.0±448.5) in non-GERD patients (p<0.001). The mean 24-h AI value was 122.1±88.1 (daytime 101.4±82.5, night-time 145.3±120.7) in GERD patients and 83.0±81.0 (daytime 71.0±73.9, night-time 96.4±102.6) in non-GERD patients (p<0.001). Our statistical modeling demonstrated that the correlation between the acidity index and IA becomes progressively poorer with increasing values of acidity. Conclusions. We conclude that gastric acid production assessed by both IA and AI is higher during evening hours in comparison with daytime hours and the difference between night-time and daytime values is statistically significant. In addition, gastric acid production assessed by both IA and AI is significantly higher in GERD patients than non-GERD patients. This difference is primarily due to differences in nocturnal acid production. The AI correlates poorly with measured IA, especially at higher levels of gastric acidity. Therefore, AI is not an acceptable surrogate for IA in assessing gastric acid production.     

Gastroesophageal and laryngopharyngeal reflux detected by 24-hour combined impedance and pH monitoring in healthy Chinese volunteers

OBJECTIVE: To define the normative data of gastroesophageal reflux (GER) and laryngopharyngeal reflux (LPR) in healthy Chinese volunteers. METHODS: Healthy volunteers without gastrointestinal and throat disease and symptoms were enrolled and underwent 24‐hour impedance‐pH monitoring. RESULTS: A total of 37 healthy volunteers completed all the tests (female 54.1%; age 38.0 ± 15.2 years). Of 1862 GER, 49.6% were mixed, 40.9% were liquid and 9.5% were gas. More than half (54.9%) were acid. The median and 95th percentile numbers of GER were 52 and 71, respectively. The number of LPR was eight, of which two were mixed and the others were liquid. Only one episode of reflux was classified as acid LPR. The median and 95th percentile numbers of LPR were 0 and 2, respectively. More liquid reflux were associated with LPR (P = 0.02). Age had no influence on GER and LPR reflux profiles. CONCLUSIONS: Few LPR occurred in healthy Chinese volunteers and they were rarely acid when they reached the larynx. LPR was mostly associated with liquid reflux.