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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Bile Reflux after Weight-Loss Surgery
Scientific title
Assessing bile reflux using endoscopy and HIDA scintigraphy in post-bariatric surgical patients
Secondary ID [1] 294750 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Bile reflux 307644 0
Obesity 307645 0
Condition category
Condition code
Surgery 306713 306713 0 0
Surgical techniques

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Patients planned to undergo weight-loss surgery (gastric bypass or sleeve gastrectomy) will be invited to join the study. The type of weight loss operation performed by the surgeon will not be affected by enrolment in this study. Pre-operatively, participants will undergo upper gastro-intestinal endoscopy with stomach (+/- oesophageal) biopsies and biochemical analysis of stomach fluid, blood testing and biometric measurements (weight, height, BMI, hip and waist circumference). Participants will also be requested to complete a symptom questionnaire.

At 6 months post-operatively, participants will undergo a HIDA scan at Royal Adelaide Hospital and a repeat endoscopy with biopsies and gastric fluid samples. They will also be invited to complete again the same GERD-Q Questionnaire, in addition to an ‘Investigations Tolerability Questionnaire’. Repeat measurements of weight, height, BMI, hip and waist circumference will also be collected.
Intervention code [1] 301050 0
Diagnosis / Prognosis
Comparator / control treatment
No control group
Control group

Primary outcome [1] 305712 0
To evaluate whether laparoscopic single anastomosis gastric bypass (LSAGB), laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) operations result in increased bile reflux 6 months post-operatively, as determined by visualisation of reflux on HIDA scanning, the presence of bile acids in the stomach and oesophagus, with or without histological stomach/oesophageal tissue damage.
Timepoint [1] 305712 0
Pre-operatively and 6 months post-operatively
Secondary outcome [1] 346222 0
To further evaluate the safety and efficacy of laparoscopic single-anastomosis gastric bypass, laparoscopic sleeve gastrectomy and laparoscopic roux-en-Y gastric bypass. as determined by complication rate, amount of weight loss and remission of obesity-related comorbidities. Complications include, but are not limited to, infection, anastomotic leak and post-operative ileus. Weight loss will be determined by change in actual weight and measurement of waist and hip circumference. Obesity related comorbidities include diabetes/ glucose intolerance and high cholesterol and will be evaluated by changes in blood results (blood glucose, HbA1c, LDL/HDL).
Timepoint [1] 346222 0
Complications will be evaulated during the participants' post-operative recovery in hospital.
Weight, waist and hip circumference will be measured pre-operatively and 6-months post-operatively.
Blood tests will be performed pre-operatively and 6-months post-operatively.
Secondary outcome [2] 346223 0
To evaluate the patient’s tolerability of investigations by surveying comfort during and after investigations, and perception of invasiveness and tolerability of investigations.
Timepoint [2] 346223 0
6 months post-operatively

Key inclusion criteria
Obesity of >5 years duration
BMI>40 or >35 plus comorbidities
Documented attempts at previous weight loss
Age 18-60
Good commitment to achieving weight loss
Suitability for bariatric surgery
Minimum age
18 Years
Maximum age
60 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Previously undergone obesity surgery
Previously undergone gastric surgery
Previously undergone gallbladder surgery
Large abdominal hernias
Pregnancy or are breast feeding
Psychiatric illness

Study design
Defined population
Statistical methods / analysis
Sample Size:
Using the best estimates of bile reflux rates for the 3 operations found in the available literature, a power calculation was performed to determine the required sample size. Taking into consideration potential variance between surgeons and operative sites, as well as a drop-out rate of 10%, our sample size is 75 (25 in each arm).

Sample analysis:
Gastric biopsies will be reviewed by a qualified histopathologist within SA Pathology to assess: markers of tissue inflammation, markers of DNA damage and presence of bile acids.

Gastric aspirates will be analysed using established assays by SA Pathology to assess: presence of bile acids, concentration of bile acids and identification of individual bile acids.

HIDA Scan analysis:
The rate of hepatobiliary excretion of the tracer utilized and amount of bile reflux will be calculated from the HIDA scans using dynamic imaging with region of interest calculations over the liver, duodenum, gastric remnant and oesophagus.

Statistical Analysis of data:
Statistical analysis will be undertaken using commercially available statistical programs in consultation with professional statistical advice from our Unit's established connection with a health research statistician. Normally distributed data will be reported as mean ± standard error of the mean and statistical comparisons between groups will be made using parametric statistical tests. Data that is not normally distributed, will be analysed using non-parametric statistics with reporting of median (interquartile range) and comparisons by applying non-parametric statistical tests, with post-hoc analysis for differences across the 3 surgical groups. Proportionate data will be compared using tests such as a Fisher’s exact test or X2 test.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 10819 0
The Queen Elizabeth Hospital - Woodville
Recruitment hospital [2] 10820 0
Calvary Wakefield Hospital - Adelaide
Recruitment hospital [3] 13619 0
The Burnside War Memorial Hospital - Toorak Gardens
Recruitment hospital [4] 13620 0
The Royal Adelaide Hospital - Adelaide
Recruitment hospital [5] 16130 0
Flinders Private Hospital - Bedford Park
Recruitment hospital [6] 16131 0
Ashford Community Hospital - Ashford
Recruitment postcode(s) [1] 22559 0
5011 - Woodville
Recruitment postcode(s) [2] 22560 0
5000 - Adelaide
Recruitment postcode(s) [3] 26287 0
5065 - Toorak Gardens
Recruitment postcode(s) [4] 29658 0
5042 - Bedford Park
Recruitment postcode(s) [5] 29659 0
5035 - Ashford

Funding & Sponsors
Funding source category [1] 299356 0
Name [1] 299356 0
Oesophageal Function Laboratory
Address [1] 299356 0
The Queen Elizabeth Hospital
28 Woodville Road
Woodville South, SA 5011
Country [1] 299356 0
Primary sponsor type
Discipline of Surgery, University of Adelaide
The Queen Elizabeth Hospital
28 Woodville Road
Woodville South, SA 5011
Secondary sponsor category [1] 298631 0
Name [1] 298631 0
Department of Nuclear Medicine
Address [1] 298631 0
Royal Adelaide Hospital
Port Road
Adelaide SA 5000
Country [1] 298631 0

Ethics approval
Ethics application status
Ethics committee name [1] 300261 0
Human Research Ethics Committee (TQEH/LMH/MH)
Ethics committee address [1] 300261 0
The Queen Elizabeth Hospital
Basil Hetzel Institute DX465101
28 Woodville Road
Woodville South SA 5011
Ethics committee country [1] 300261 0
Date submitted for ethics approval [1] 300261 0
Approval date [1] 300261 0
Ethics approval number [1] 300261 0
Ethics committee name [2] 300262 0
Calvary Health Care Adelaide (CHCA) Human Research Ethics Committee
Ethics committee address [2] 300262 0
Calvary Wakefield Hospital
300 Wakefield Street
Adelaide SA 5000
Ethics committee country [2] 300262 0
Date submitted for ethics approval [2] 300262 0
Approval date [2] 300262 0
Ethics approval number [2] 300262 0

Brief summary
We are assessing the occurrence of bile reflux in patients who have undergone weight-loss operations. Bile reflux can predispose to oesophagitis, Barrett’s oesophagus and even oesophageal cancer. A new surgical technique has been developed and shows excellent results with regard to weight loss, remission of diabetes and safety. This technique is controversial, however, with an increased theoretical risk of bile reflux. Our study will provide additional data on the safety of weight loss operations, both generally and specifically relating to bile reflux, impacting surgical decision making in bariatric surgery. The results from our study will provide clinicians with clear evidence from which they can make informed decisions about the safety of the 'new' surgical technique. With current data showing favourable results, including improved efficacy and decreased risk of complications, increased utilisation of the technique will result in improved short-term and long-term patient outcomes. Awareness of the incidence of bile reflux post-operatively will allow clinicians to treat any reflux early, preventing or at least delaying potentially detrimental health outcomes. These interventions will translate into decreased health expenditure, providing net health and economic benefit.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 83082 0
Mr Jon Shenfine
Address 83082 0
Flinders Medical Centre
Flinders Drive
Bedford Park SA 5042
Country 83082 0
Phone 83082 0
+61 8 8204 5511
Fax 83082 0
Email 83082 0
Contact person for public queries
Name 83083 0
Dr Thomas Eldredge
Address 83083 0
Department of Surgery
The Queen Elizabeth Hospital
28 Woodville Road
Woodville South SA 5011
Country 83083 0
Phone 83083 0
Fax 83083 0
Email 83083 0
Contact person for scientific queries
Name 83084 0
Dr Thomas Eldredge
Address 83084 0
Department of Surgery
The Queen Elizabeth Hospital
28 Woodville Road
Woodville South SA 5011
Country 83084 0
Phone 83084 0
Fax 83084 0
Email 83084 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
No necessary
What supporting documents are/will be available?
Study protocol
Informed consent form
How or where can supporting documents be obtained?
Type [1] 7370 0
Study protocol
Citation [1] 7370 0
Link [1] 7370 0
Email [1] 7370 0
Other [1] 7370 0
Type [2] 7371 0
Informed consent form
Citation [2] 7371 0
Link [2] 7371 0
Email [2] 7371 0
Other [2] 7371 0
Summary results
No Results