2.1. Study design
This was a single-center, stratified (diabetes mellitus (DM) and non-diabetes mellitus) with gender balanced randomisation (1:1), single-blinded, placebo-controlled, parallel-group study regarding the effect of pre-endoscopy beverage served at 2 hours prior to the outpatient upper endoscopic procedure. The endoscopists that performed this procedure and the staff nurse assessing the patient’s well-being both blinded.
All methods were approved by the Human Research Ethics Committee, Universiti Sains Malaysia in Kelantan, Malaysia (Institutional Review Board registration number: USM/JEPeM/20080414). All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation and with the 1975 Declaration of Helsinki (6th revision, 2008). Written informed consent was obtained from all participants before randomization. This study was registered at the clinicaltrial.gov (NCT05106933 on 04/11/2021). Study protocol was performed according to the CONSORT statement and checklist.
2.2. Participants
Patients who were scheduled for elective gastroscopy from January to August 2021 were invited to participate voluntarily in this study. Patients aged more than 18 years and agreed to participate in the study were included in the study. Patients with history of upper gastrointestinal surgery, clinically unstable condition and with active upper GI bleeding were excluded from the study. Pregnant lady and patients who were on nasogastric feeding tube were also not eligible for this study as it may interrupt the measurement of GRV. This study was conducted in the Endoscopy Unit, Hospital Universiti Sains Malaysia, Kubang Kerian, Malaysia. A total of 80 patients who fulfilled the inclusion criteria were selected for randomisation process.
2.3. Intervention
For allocation of the participants, a computer-generated list of random numbers was used, which was prepared by an investigator with no clinical involvement in the study. Randomisation sequence was created using https://www.sealedenvelope.com/simple-randomiser/v1/lists and was stratified by patients who having DM and non-DM with a 1:1 allocation using random block size of 6.
The allocation sequence was concealed from researcher enrolling and assessing participants in sequentially numbered, opaque, sealed and stapled envelopes. To prevent subversion of the allocation sequence, the name and identification number of the participant was written on a book together with the serial number on the envelope. The details in the book were kept confidentially. Only after the enrolled participants completed all baseline assessments, the corresponding envelope was opened by the trained staff who involved in preparing the drink. The staff need to ensure that the envelop was still sealed when receiving it. The staff prepared the drink into an identical container according to randomisation.
Participants were randomised into control group (group A, 400 ml plain water) and maltodextrin beverage group (group B, 400 ml of Carborie®, 50 gm of carbohydrate, protein-free) (Valens Nutrition, Kuala Lumpur, Malaysia). Participants consumed the drink over 10 minutes. Participants were not allowed to leave the endoscopy room until their procedure were completed to prevent consumption of other drinks or foods. Gastroscopy was performed after 2 hours of beverage consumption, following the standard protocol. The endoscopist was advice to use only air inflation and not to use any water flushing; only lens flushing was allowed to ensure clear visualization of the gastric content. The visualized pooling of fluid within the stomach was then aspirated via direct visualisation with the endoscope. The aspirated fluid was collected in the suction reservoir to be recorded as GRV.
Participant’s well-being score (consisted of 5 parameters included hunger, thirst, anxiety, tiredness and general discomfort) was assessed using visual analogue scale (VAS). Each scale consisted of ungraded, horizontal lines anchored at two ends. The left end of the scale represented “not at all” which score: 0 mm and the right end represented and “the most imaginable” which score: 100 mm. The trained staff nurse asked the participant regarding the level of 5 parameters and the participant marked an [X] somewhere along the horizontal line to complete the scale before administration of the drink and before OGDS procedure.
2.4. Outcomes
The primary objective was to compare GRV (ml) between participant in plain water group (group A) and carbohydrate loading group (group B). The aspirated fluid was collected in the suction reservoir and GRV was measured. The second objective was to compare patient’s well-being score for group A and B. Participant’s well-being score was assessed using VAS which consisted of 5 parameters: hunger, thirst, anxiety, tiredness and general discomfort.
2.5. Sample size estimation
The sample size was calculated using two means formula using http://www.openepi.com/SampleSize/SSMean.html 10 for the first objective and paired difference formula using http://statulator.com/SampleSize/ss2PM.html for the second objective.
For the first objective, which is to compare GRV between the two groups, the ratio of sample size (group A/group B) was set as 1. The sample size was calculated using the standard deviation (18.46 ml) and difference between the means (12.5 ml). Based on these two estimates, the calculated sample size for this objective was 35 subjects per group.
For the second objective, which is to determine patient’s well-being for group A and B, the expected standard deviation of the paired differences (14) was set as 2 times the expected mean of the paired differences (7). The calculated sample size for the second objective was 34 subjects per group. The final calculated sample size was 39 subjects per group (with two-sided 5% significant level and a power of 80%, in view of dropout rate of 10%).
2.6. Statistical analysis
The numerical data were presented as mean and standard deviation (SD) or median and interquartile range (IQR) for continuous data depending on their normality. For categorical data, frequency and percentage were used. Primarily, the normality of data distribution was evaluated by the box plot, graph and test of normality for both groups. To compare GRV between the two groups, the Mann-Whitney U test was performed. The Wilcoxon signed-rank test was used to compare participants’ well-being scores before and after administration of the drink in each group. The Mann-Whitney U test was conducted to compare patient’s well-being score between group A and B before and after administration of the drink. Data analyses were performed using IBM SPSS Statistics for Windows, Version 27.0 (IBM Corp., Armonk, NY, USA). The limit of significance was set at 0.05.