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Trial registered on ANZCTR


Registration number
ACTRN12619001505190
Ethics application status
Approved
Date submitted
26/09/2019
Date registered
31/10/2019
Date last updated
23/04/2021
Date data sharing statement initially provided
31/10/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
Predicting the successful resolution of Obstructive Sleep Apnoea following weight-loss surgery
Scientific title
Predicting the successful resolution of Obstructive Sleep Apnoea following weight-loss surgery
Secondary ID [1] 294636 0
None
Universal Trial Number (UTN)
Trial acronym
BAROSA
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obstructive Sleep Apnoea 307484 0
Obesity 307485 0
Condition category
Condition code
Respiratory 306566 306566 0 0
Sleep apnoea
Diet and Nutrition 306567 306567 0 0
Obesity

Intervention/exposure
Study type
Observational
Patient registry
True
Target follow-up duration
12
Target follow-up type
Months
Description of intervention(s) / exposure
Longitudinal study of Obstructive Sleep Apnoea (OSA) patients scheduled to undergo weight-loss surgery with a Sleeve Gastrectomy. Patient's sleep (i.e. OSA severity) and physiological traits will be assessed via two overnight sleep studies before surgery and at 12-month post-surgery in order to assess how the trajectory of weight-loss over time relates to the improvement in OSA and its underlying physiology.
Intervention code [1] 300940 0
Not applicable
Comparator / control treatment
No control group
Control group
Uncontrolled

Outcomes
Primary outcome [1] 305572 0
OSA severity as assessed using Apnoea/Hypopnea Index from overnight polysomnography data
Timepoint [1] 305572 0
Pre-surgery baseline and 12-month post bariatric surgery
Primary outcome [2] 305573 0
Upper airway anatomy measured using a physiological sleep study (this involves placing the participant on CPAP, manipulating the pressure while they sleep and measuring the corresponding changes in breathing).
Timepoint [2] 305573 0
Pre-surgery baseline and 12-month post bariatric surgery
Primary outcome [3] 321839 0
Loop gain measured using a physiological sleep study (this involves placing the participant on CPAP, manipulating the pressure while they sleep and measuring the corresponding changes in breathing).
Timepoint [3] 321839 0
Pre-surgery baseline and 12-month post bariatric surgery
Secondary outcome [1] 345794 0
Subjective sleepiness as assessed using the Epworth Sleepiness Scale
Timepoint [1] 345794 0
Pre-surgery baseline and 12-month post bariatric surgery
Secondary outcome [2] 345795 0
Awake upper airway volumes (assessed using MRI scans)
Timepoint [2] 345795 0
Pre-surgery baseline and 12-month post bariatric surgery
Secondary outcome [3] 345796 0
Lung function as assessed using spirometry
Timepoint [3] 345796 0
Pre-surgery baseline and 12-month post bariatric surgery
Secondary outcome [4] 345797 0
Diastolic and systolic blood pressure (sphygmomanometer)
Timepoint [4] 345797 0
Pre-surgery baseline and 12-month post bariatric surgery
Secondary outcome [5] 368913 0
Body composition (Dual Energy X-ray Absorptiometry, Body Mass Index, weight and anthropomorphic measurements of neck, hip and waist circumference).
Timepoint [5] 368913 0
Pre-surgery baseline and 12-month post bariatric surgery
Secondary outcome [6] 376432 0
Upper airway muscle compensation measured using a physiological sleep study (this involves placing the participant on CPAP, manipulating the pressure while they sleep and measuring the corresponding changes in breathing).
Timepoint [6] 376432 0
Pre-surgery baseline and 12-month post bariatric surgery
Secondary outcome [7] 376433 0
Arousal threshold measured using a physiological sleep study (this involves placing the participant on CPAP, manipulating the pressure while they sleep and measuring the corresponding changes in breathing).
Timepoint [7] 376433 0
Pre-surgery baseline and 12-month post bariatric surgery

Eligibility
Key inclusion criteria
• Ability to consent
• Moderate/severe OSA (Apnoea Hypopnea Index [AHI] > 15)
• Body Mass Index (BMI) of 35-55
• Scheduled to undergo a sleeve gastrectomy surgery for weight-loss
• Patients will be otherwise healthy (except for treated hypertension and diabetes)
Minimum age
18 Years
Maximum age
65 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
• Untreated medical problems other than OSA
• Patients with safety concerns (drowsy driving within the past 1 year)
• Receiving medication that could affect ventilation (i.e. morphine derivatives, benzodiazepines, theophylline) or muscle control.
• Allergy to lidocaine or oxymetazoline
• Previous surgical treatment for OSA and/or obesity
• Women who are pregnant or breastfeeding

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Defined population
Timing
Prospective
Statistical methods / analysis
Sample size calculations:
The primary metrics used to determine the effect of weight loss on sleep apnea severity will be the predicted improvement in the traits causing OSA; upper airway anatomy, arousal threshold, pharyngeal dilator muscle function and loop gain. The sample size estimation for this investigation was based on being able to detect a meaningful difference in loop gain, for which there was the smallest change before and after weight loss in our preliminary data (n=6).

A sample size of 19 Bariatric/OSA patients will give 80% power with a 2-sided alpha of 0.05 to detect a mean change in loop gain of 1.4 ± 2.0 (Mean ± SD). Therefore, to allow for participant attrition (approximately 20%) 24 subjects will be recruited. This number is also more than adequate for assessing the change in OSA severity based on the data of Dixon et al (2012, JAMA) which showed a mean reduction in AHI of 25.5 ± 30.1 (Mean ± SD) in the surgical group. A sample size of 19 with a 2-sided alpha of 0.05, will give us 92% power to detect differences in the AHI.


Outcome/Statistical Analysis:
Aim 1: Linear mixed effects models will be used to evaluate the relationship between BMI and each of the 4 OSA traits with the use of a random intercept and slope for each subject. A similar model will be generated modelling AHI as a function of BMI. To this model, each of the four traits will then be added one at a time to determine the impact of accounting for that trait on the AHI-BMI relationship. Demonstrating a reduction in the BMI coefficient with inclusion of an OSA trait will be judged as evidence supporting a causal role for that trait in mediating the effect of obesity on OSA severity. In secondary analyses, we will examine these relationships with other measures of obesity (i.e. neck, waist & hip circumference, various MRI outcome measures).

Aim 2: We will identify physiological (the 4 OSA traits) and clinical (anthropometric variables, ESS etc.) factors that are significant predictors of OSA treatment success at 12 months.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment hospital [1] 10745 0
The Avenue Private Hospital - Windsor
Recruitment postcode(s) [1] 22471 0
3181 - Windsor

Funding & Sponsors
Funding source category [1] 299254 0
Government body
Name [1] 299254 0
National Health and Medical Research Council
Address [1] 299254 0
Postal address
GPO Box 1421
Canberra ACT 2601

Physical address
414 La Trobe St
Melbourne VIC 3000
Country [1] 299254 0
Australia
Primary sponsor type
University
Name
Monash University
Address
Department of Physiology and School of Psychological Sciences
Faculty of Medicine, Nursing and Health Sciences | Monash University
264 Ferntree Gully Road | Notting Hill, VIC 3168, Australia
Country
Australia
Secondary sponsor category [1] 304187 0
None
Name [1] 304187 0
Address [1] 304187 0
Country [1] 304187 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 300172 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 300172 0
Room 111, Chancellery Building D,
26 Sports Walk, Clayton Campus
Research Office
Monash University VIC 3800
Ethics committee country [1] 300172 0
Australia
Date submitted for ethics approval [1] 300172 0
27/03/2018
Approval date [1] 300172 0
02/05/2018
Ethics approval number [1] 300172 0
12010

Summary
Brief summary
Obstructive sleep apnoea (OSA) is a common disorder and is an independent risk factor for cardiovascular morbidity and mortality, making OSA a major health concern. Importantly obesity, which is the strongest risk factor for OSA, is a growing epidemic and is one the western world’s leading health care concerns. However, the exact mechanisms by which obesity increases the risk of OSA are poorly understood. Therefore, this study aims to examine the effect that obesity has on the underlying physiology known to cause OSA. Using well-established physiological and imaging techniques, we will measure the physiology both before and after weight loss surgery in a group of obese OSA patients. Additionally, using all the variables measured in this study, we aim to be able to predict the important factors involved in the successful resolution of OSA following weight loss. Understanding the important factor(s) involved linking obesity with OSA is crucial for developing more effective interventions and treatment strategies.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 82782 0
Dr Bradley Edwards
Address 82782 0
Department of Physiology and School of Psychological Sciences
Faculty of Medicine, Nursing and Health Sciences | Monash University
264 Ferntree Gully Road | Notting Hill, VIC 3168
Country 82782 0
Australia
Phone 82782 0
+613 9905 0187
Fax 82782 0
Email 82782 0
bradley.edwards@monash.edu
Contact person for public queries
Name 82783 0
Dr Bradley Edwards
Address 82783 0
Department of Physiology and School of Psychological Sciences
Faculty of Medicine, Nursing and Health Sciences | Monash University
264 Ferntree Gully Road | Notting Hill, VIC 3168
Country 82783 0
Australia
Phone 82783 0
+613 9905 0187
Fax 82783 0
Email 82783 0
bradley.edwards@monash.edu
Contact person for scientific queries
Name 82784 0
Dr Bradley Edwards
Address 82784 0
Department of Physiology and School of Psychological Sciences
Faculty of Medicine, Nursing and Health Sciences | Monash University
264 Ferntree Gully Road | Notting Hill, VIC 3168
Country 82784 0
Australia
Phone 82784 0
+613 9905 0187
Fax 82784 0
Email 82784 0
bradley.edwards@monash.edu

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
OSA physiology and severity measurements pre and post surgery
When will data be available (start and end dates)?
Start: Following completion of all baseline (pre-surgery) assessments (approximately December 2020)
End: No end date determined
Available to whom?
Research collaborators at the University of Queensland and Harvard Medical School (Boston, USA).
Available for what types of analyses?
Testing and validating algoryhtms to assess OSA physiology non-invasively and predict outcomes.
How or where can data be obtained?
De-identified data will be shared by a secure file transfer program (i.e. CloudStor)
What supporting documents are/will be available?
No other documents available
Summary results
No Results