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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
Date results information initially provided
Type of registration
Retrospectively registered

Titles & IDs
Public title
Determining the gut bacteria in the setting of high blood pressure
Scientific title
Determining the gut microbiota in normotensive and hypertensive patients with ambulatory blood pressure
Secondary ID [1] 301733 0
Nill known
Secondary ID [2] 301734 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
318190 0
gut microbiota 318191 0
Condition category
Condition code
Cardiovascular 316201 316201 0 0

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Participants will have blood pressure measured in the office (over 3 times, after being seated for 5 minutes) and over 24 hours with an ambulatory blood pressure device (every 15 minutes during the day and every 30 minutes during the night), will have plasma collected (once), complete a food frequency questionnaire which covers a 12 month period (The Dietary Questionnaire for Epidemiological Studies - DQES v3.2), and will self-collect one fecal sample after the 24 hours blood pressure measurement. Participants saw the principal investigator, who has more than 8 years of experience in the field, or one of the research nurses. The visit was face-to-face, and we saw each participant once (day of the visit). Equipment and fecal samples were returned to the reception of the sites. Recruitment was performed at the Alfred Hospital, Melbourne, VIC, Australia, and at the Modern Clinic, Shepparton, VIC, Australia.
Intervention code [1] 318033 0
Diagnosis / Prognosis
Comparator / control treatment
Participants with systolic blood pressure <140 mmHg and diastolic blood pressure <90 mmHg
Control group

Primary outcome [1] 324384 0
Changes in the gut microbiota (taxa and diversity by next-generation sequencing)
Timepoint [1] 324384 0
24 hours after the study visit
Secondary outcome [1] 386326 0
Gut metabolites (short-chain fatty acids in plasma and fecal samples, by gas chromatography)
Timepoint [1] 386326 0
Once, from plasma collected during study visit

Key inclusion criteria
For normotensive participants:
• Diagnosis of normal blood pressure: Systolic blood pressure <140 mmHg and diastolic blood pressure <90 mmHg
• Age: 40-70 years old
• Gender: either
• Body mass index: 18.5-30

For hypertensive participants:
• Diagnosis of hypertension: Systolic blood pressure >140 mmHg and diastolic blood pressure >90 mmHg
• Age: 40-70 years old
• Gender: either
• Body mass index: 18.5-30

Minimum age
40 Years
Maximum age
70 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Type 1 or type 2 diabetes, chronic kidney disease, gastrointestinal diseases (including history of intestinal surgery, inflammatory bowel disease, celiac disease, lactose intolerance, chronic pancreatitis or other malabsorption disorder), use of probiotics or antibiotics in the past 3 months, and taking medication for hypertension.

Study design
Case control
Statistical methods / analysis

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] 17047 0
The Alfred - Melbourne
Recruitment postcode(s) [1] 30717 0
3004 - Melbourne

Funding & Sponsors
Funding source category [1] 306171 0
Other Collaborative groups
Name [1] 306171 0
Baker Heart and Diabetes Institute
Address [1] 306171 0
Baker Heart and Diabetes Institute
75 Commercial Rd, Melbourne VIC 3004
Country [1] 306171 0
Primary sponsor type
Dr Francine Marques
Baker Heart and Diabetes Institute
75 Commercial Rd, Melbourne VIC 3004
Secondary sponsor category [1] 306641 0
Other Collaborative groups
Name [1] 306641 0
Heart Failure Research Laboratory
Address [1] 306641 0
Baker Heart and Diabetes Institute
75 Commercial Rd, Melbourne VIC 3004
Country [1] 306641 0

Ethics approval
Ethics application status
Ethics committee name [1] 306383 0
Alfred Hospital Ethics Committee
Ethics committee address [1] 306383 0
55 Commercial Rd, Melbourne VIC 3004
Ethics committee country [1] 306383 0
Date submitted for ethics approval [1] 306383 0
Approval date [1] 306383 0
Ethics approval number [1] 306383 0

Brief summary
High blood pressure, also known as hypertension, is a disease where the blood inside the heart and blood vessels is pumped with more force than normal. This adds stress to these important tissues, increasing the chance of a heart attack, stroke and, as we age, heart failure. Hypertension affects one in three people in Australia, and is known as a ‘silent disease’ as it usually does not produce any symptoms until it might be too late.

It is well known that our diet influences the risk to high blood pressure. While salt intake is associated with higher blood pressure, consumption of fruit, vegetables and other food rich in fibre is usually associated with lower blood pressure. New evidence from our laboratory has emerged that this may be due to the tiny microorganisms that live in our gut. While our bodies are incapable of digesting some types of fibre, they are fermented in gut, where they feed the community of ‘good’ bacteria. This results in the release of substances that can be detected in our blood and might be beneficial in lowering our blood pressure.

The present study will expand our knowledge about the gut bacteria in the setting of normal and high blood pressure, to help us understand the types of bacteria present in hypertensive subjects and whether they could be contributing to the increase in blood pressure. This research has implications for cardiovascular health due to the relatively benign and cost effective nature of diet treatments. It will also inform on future intervention strategies and food guidelines.

Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 103694 0
A/Prof Francine Marques
Address 103694 0
Monash University
25 Rainforest Walk, Clayton 3800 VIC
Country 103694 0
Phone 103694 0
Fax 103694 0
Email 103694 0
Contact person for public queries
Name 103695 0
A/Prof Francine Marques
Address 103695 0
Monash University
25 Rainforest Walk, Clayton 3800 VIC
Country 103695 0
Phone 103695 0
Fax 103695 0
Email 103695 0
Contact person for scientific queries
Name 103696 0
A/Prof Francine Marques
Address 103696 0
Monash University
25 Rainforest Walk, Clayton 3800 VIC
Country 103696 0
Phone 103696 0
Fax 103696 0
Email 103696 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
Individual 16S (microbiome) sequencing from each participant data underlying published results only
When will data be available (start and end dates)?
Immediately following publication, no end date
Available to whom?
Anyone who wishes to access it
Available for what types of analyses?
Any purpose
How or where can data be obtained?
Access subject to approvals by Principal Investigator (A/Prof Francine Marques,, P: +61-03-85321916)
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary