Abstract
Objective:
Functional dyspepsia is a heterogeneous disorder and different pathophysiological mechanisms underlie its symptom patterns. This study investigated the relationship between dyspepsia symptoms and overall and proximal gastric emptying in patients with functional dyspepsia.
Methods:
A total of 93 patients with functional dyspepsia and 32 healthy subjects were enrolled in this cross-sectional study. Prevalence and severity of eight dyspepsia symptoms were recorded. Gastric emptying was measured using single photon emission computed tomography scanning.
Results:
Overall and proximal gastric emptying were delayed in 47.3% (44/93) and 46.2% (43/93) of the patients, respectively. Logistic regression analyses showed that presence of nausea was associated with delayed proximal gastric emptying (odds ratio 4.951; 95% confidence interval 1.321, 18.558). There were no significant differences between normal and delayed overall gastric emptying according to presence of symptoms.
Conclusions:
Presence of nausea might indicate delayed gastric emptying of the proximal stomach. Promotion of proximal gastric emptying may constitute an effective therapy for patients with functional dyspepsia who report nausea as the dominant symptom.
Keywords
Introduction
According to the Rome III criteria, functional dyspepsia is defined as the presence of at least one of the following, in the absence of organic disease that is likely to explain the symptoms: bothersome postprandial fullness; early satiation; epigastric pain; epigastric burning. 1 Symptoms must be present for the 3 months preceding diagnosis and have an onset ≥ 6 months before diagnosis. Research has shown that the incidence of functional dyspepsia is 16%, 2 and that it accounts for ∼ 40% of the total outpatient population of gastroenterology departments. 3 Functional dyspepsia does not shorten life expectancy, but it seriously affects health-related quality of life and consumes extensive medical resources. 4
Functional dyspepsia is a heterogeneous disease with an unclear pathophysiology. Different symptom patterns may be associated with variable disease mechanisms. Delayed gastric emptying occurs in about 23 – 59% of patients with functional dyspepsia. 5 Some research has shown that delayed gastric emptying may be related to postprandial fullness and vomiting, with these symptoms being more frequently found in female patients than in males.6–8 Other studies have failed to confirm any difference in the occurrence of functional dyspepsia symptoms between patients with normal or delayed gastric emptying.9,10 It is clinically important to confirm the presence of delayed gastric emptying in symptomatic patients so that they can receive the most appropriate treatment.
The relationship between symptoms and gastric solid emptying in patients with functional dyspepsia has not been studied in detail and there have been few studies in Asian populations. Given the paucity of data, the purpose of the present study was to determine the proportion of patients with functional dyspepsia who also have delayed gastric emptying (overall or proximal stomach) using scintigraphy, the gold-standard method for assessing gastric solid emptying function. This study also investigated the relationship between delayed gastric emptying (overall or proximal stomach) and symptom patterns of functional dyspepsia.
Patients and methods
Study Population
This was a cross-sectional study conducted in the Department of Gastroenterology, China-Japan Friendship Hospital, Ministry of Health (a tertiary referral centre), Beijing, China, between October 2009 and November 2011. Consecutive adult patients with dyspepsia symptoms, presenting to outpatient gastroenterology clinics, were invited to participate in this study. All recruited patients received a physical examination, performed by experienced gastroenterologists (S-K.Y ., Y-L.Z.). Medical histories were documented and patients were subjected to endoscopy of the alimentary tract using the Olympus CV-260SL video processor (Olympus Medical Systems, Tokyo, Japan), routine blood biochemistry tests and abdominal ultrasound using the Phillips iU22 system (Royal Phillips Electronics, Amsterdam, the Netherlands). Medications that might affect gastrointestinal (GI) function (including antidepressants) were discontinued for 1 week prior to any examination.
All patients fulfilled the Rome III criteria after assessment; 1 they reported one or more of four symptoms including postprandial fullness, early satiety, epigastric pain or epigastric burning. Symptoms must have been present for the 3 months preceding diagnosis and have occurred for 6 months before diagnosis. Patients presented no evidence of organic disease that could be responsible for these symptoms. Exclusion criteria included: oesophagitis; atrophic gastritis or gastro-oesophageal erosion diagnosed by endoscopy; mental disorder; history of alimentary tract ulceration; abdominal surgery; administration of nonsteroidal anti-inflammatory drugs, hormones or other medications that can affect gastric acid secretion within 6 months of study entry.
During upper GI endoscopy, tissue biopsies were taken from the antrum and the corpus, and immediately fixed in 10% neutral-buffered formalin for 24 h at room temperature. Tissues were then dehydrated in ethanol, cleared in xylene and embedded in paraffin wax. Representative sections (4-μm thick) were cut and mounted onto poly-L-lysine-coated slides. Specimens were then stained with cresyl violet to detect the presence of
Healthy (control) subjects were recruited by advertisements in the hospital, and consisted of volunteers from local colleges and companies; none of these volunteers were patients attending another hospital clinic. All healthy subjects were required to have no symptoms of functional dyspepsia and no history of alimentary tract diseases or drug allergy. They were subjected to upper GI endoscopy, routine biochemistry panels and abdominal ultrasound as undertaken for patients with functional dyspepsia, to exclude alimentary tract diseases.
The study was approved by the Ethics Committee of the China-Japan Friendship Hospital, and written informed consent was obtained from all study participants.
Dyspepsia Symptom Questionnaire
Demographic data and dyspepsia symptoms in recruited patients with functional dyspepsia were collected by means of the validated Rome III questionnaire. 11 On the questionnaire, the intensity of functional dyspepsia symptoms (including postprandial fullness, early satiety, epigastric pain, burning, bloating, nausea, vomiting or belching) was divided into four grades: no symptoms, 0; mild symptoms, 1 (only felt when attention was paid to them); moderate symptoms, 2 (tolerable, but sometimes affecting normal life and work); serious symptoms, 3 (intolerable, significantly affecting normal life and work). Due to the relatively small number of patients included in the present study, prevalence of dyspepsia symptoms was not presented by severity. Patients with functional dyspepsia were required to complete the symptom questionnaire based on their condition in the previous 3 months. They were also asked about changes in their body weight since the onset of disease.
Gastric Emptying Studies
Gastric emptying was assessed in patients with functional dyspepsia and healthy subjects at the Department of Nuclear Medicine, China-Japan Friendship Hospital. After an overnight fast of 10 h, participants arrived at the hospital in the morning and were asked to ingest a standard meal that consisted of 50 g scrambled egg and 400 ml of noodle soup, labelled with 2 mCi 99mtechnetium-labelled diethylene-triamine-pentacetate (99mTc-DTPA). The meal had a calorific value of 500 kcal (nutritional composition: 14 g protein, 21 g fat, 64 g carbohydrate), was prepared immediately before the test and was consumed by each participant within 10 min. Immediately after meal intake, patients laid supine on the examination bed, to reduce overlapping of the stomach and small intestines. Image acquisition was initiated immediately after completion of the meal (0 min); subsequent images were obtained every 15 min for 120 min, using a double transducer single-photon emission computed tomography scanner (Millennium VG Hawkeye; GE Healthcare Biosciences, Piscataway, NJ, USA); nine images were acquired. In each time period, 1-min anterior and posterior images were collected. Radioactivity calibration and anterior–posterior calibration were performed. 12 Scintigraphic images were obtained with a large field-of-view gamma camera (Millennium VG Hawkeye, GE Healthcare Biosciences) using a low-energy all-purpose collimator with a 20% energy window setting centred at 140 keV. During the interval between two image acquisitions, participants rested in a sitting position. Females were not examined during a menstrual period in order to avoid the effect of hormone levels on rates of gastric emptying.
A nuclear medicine physician (L-J.Y.) and a gastroenterologist (Y-L.Z.) analysed and processed the acquired data, and delineated the region of interest (ROI) on each image. A radioactive count of the ROI was calculated, and standard gastric emptying curves were obtained after radioactive decay correction and anterior–posterior calibration. Measurement of proximal stomach emptying was achieved by drawing a horizontal ROI from the incisura angularis of the stomach that was extended around the stomach orad to this line. In order to identify the incisura angularis, initial or subsequent scans that identified the angle of the stomach were carefully studied, such that the same ROI could then applied to all subsequent gastric images to determine proximal stomach emptying. 13
Observation parameters included the overall gastric emptying half-time (time [min] needed for half emptying of a standard meal in the total stomach [overall GE
Statistical Analyses
The overall GE
All statistical analyses were performed using the SPSS® statistical package, version 15.0 (SPSS Inc., Chicago, IL, USA) for Windows®. All data were presented as mean ± SD. Age and body mass index (BMI) in both patient subgroups (normal versus delayed emptying) were compared using the Student's
Results
A total of 93 consecutive adult patients with dyspepsia symptoms participated in this study: 38 were male and 55 were female (mean ± SD age, 39.59 ± 12.50 years). A total of 32 healthy subjects also participated in the study; 15 were male and 17 were female (mean ± SD age, 27.34 ± 7.47 years). The mean age of the healthy subjects was significantly lower than that of the patients with functional dyspepsia (
Prevalence of eight dyspepsia symptoms in patients diagnosed with functional dyspepsia (
The mean ± SD overall GE
There were no significant differences in age, sex distribution, BMI or prevalence of
Comparison of the prevalence of eight dyspepsia symptoms in patients with functional dyspepsia with either normal ( Comparison of the prevalence of eight dyspepsia symptoms in patients with functional dyspepsia with either normal (

Comparison of demographic characteristics of patients with functional dyspepsia (
Data presented as mean ± SD or
85/93 patients received a test for
No statistically significant between-group differences (
Student's
Discussion
Research into the mechanisms involved in functional dyspepsia has focused on abnormal gastric emptying function, visceral hypersensitivity, decreased compliance, abnormal autonomic nervous function,
Delayed gastric emptying is generally considered to be one of the most important pathogenic factors in functional dyspepsia, but no consensus has been reached regarding the relationship between symptoms and gastric emptying. Sarnelli
Gastric emptying scintigraphy is the gold-standard method for testing gastric solid emptying function. 25 The present study utilized gastric emptying scintigraphy to demonstrate that nearly half (47.3%) of the patients with functional dyspepsia who were studied had delayed overall gastric emptying. No significant differences were observed, however, between patients with normal or delayed overall gastric emptying in terms of the prevalence of functional dyspepsia symptoms. Postprandial fullness was not found to be related to delayed gastric emptying; the majority of patients with functional dyspepsia reported this symptom (97.8%, 91/93) and there was no significant difference in the prevalence of postprandial fullness between patients with normal or delayed overall gastric emptying (95.9% versus 100% of patients, respectively). It is possible that differences may become apparent if the sample size was increased or if functional dyspepsia symptoms were staged according to severity.
Previous reports have mainly concentrated on the relationship between gastric solid emptying of the overall stomach and functional dyspepsia symptoms.6,8,17,24,26 Few studies have dealt with the relationship between gastric solid emptying of the proximal stomach and symptoms. In a study that compared food distribution in the stomachs of healthy subjects and patients with functional dyspepsia, postprandial fullness was found to be related to food retention in the proximal stomach late after meal ingestion.
27
The present study attempted to clarify the relationship between the gastric solid emptying function of the proximal stomach and functional dyspepsia symptoms. Delayed proximal gastric emptying occurred in almost half of the patients (46.2%) with functional dyspepsia, which was consistent with the rate of delayed overall gastric emptying. Single-factor analysis revealed that the prevalence of nausea and belching were both significantly higher in the delayed proximal gastric emptying group compared with the normal group. When age, sex, BMI,
The findings of the present study suggest that assessment of gastric emptying in patients with functional dyspepsia should also include an examination of proximal gastric emptying, in addition to the measurement of overall gastric emptying. These results are clinically important in terms of the diagnosis and treatment of functional dyspepsia, because the pathogenesis of symptoms can be easily determined in patients who report nausea as the dominant symptom, according to the correlation between nausea and delayed proximal gastric emptying. Functional dyspepsia symptoms could be alleviated with the use of prokinetic agents without the need to undertake GI function tests. Based on symptomatology, patients with functional dyspepsia could be specifically treated according to the correlation between symptoms and pathogenesis. As such, the present findings might be useful in the study of drugs that promote gastric motility. The relationship between improvement of gastric emptying and alleviation of functional dyspepsia symptoms is unclear; in fact, some investigations have reached the opposite to the conclusions presented herein:28,29 a discrepancy that might be related to participant selection. Findings of the present study suggest that, in patients diagnosed with delayed gastric emptying of the proximal stomach according to the symptom of nausea or determined by gastric emptying function tests, the use of medications that promote gastric motility may alleviate the symptoms.
Major limitations of the present study were the relatively low number of patients with functional dyspepsia analysed and the fact that it was a cross-sectional study, which permits the drawing of conclusions about associations, but not about causal or temporal relationships between variables studied or directionality of the associations found. In addition, the patients with functional dyspepsia were consecutively recruited from a tertiary care centre, which limits the generalizability of the results towards other populations of patients with the disease. Furthermore, the patients with functional dyspepsia were significantly older than the healthy subjects studied.
In conclusion, delayed gastric emptying of the overall or proximal stomach occurs in approximately half of all patients with functional dyspepsia. The presence of nausea was found to be related to delayed gastric emptying of the proximal stomach. Promotion of proximal gastric emptying function may, therefore, constitute an effective therapy for patients with functional dyspepsia who report nausea as the dominant symptom.
Footnotes
Acknowledgements
This study was supported by grant number 2007BAI20B0901 from the National Key Technology R&D Programme in the 11th 5-Year Plan of China.
The authors had no conflicts of interest to declare in relation to this article.
