Trial Review

The ANZCTR website is back online for trial registration and updates. We apologise for any inconvenience caused while the site was inactive.


With activity expected to increase on the ANZCTR again, there may be extended wait times while we process pending studies, with priority being given to those trials submitted in February. Thank you for your patience.


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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR


Registration number
ACTRN12620001121954
Ethics application status
Approved
Date submitted
20/08/2020
Date registered
29/10/2020
Date last updated
15/08/2023
Date data sharing statement initially provided
29/10/2020
Date results provided
15/08/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
Breathing control and vein function in hypertension
Scientific title
Peripheral chemoreflex regulation of sympathetic outflow and venous function using pyridoxine supplements in human hypertension
Secondary ID [1] 302046 0
nil known
Universal Trial Number (UTN)
U1111-1248-3119
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hypertension 318645 0
Condition category
Condition code
Cardiovascular 316658 316658 0 0
Hypertension

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Daily oral pyridoxine supplement (5 mg·kg-1·day-1) will be taken in pill form for 4 weeks. Adherence of intervention will be confirmed with drug tablet return and laboratory tests.
Intervention code [1] 318353 0
Treatment: Drugs
Comparator / control treatment
Placebo (microcellulose) pill
Control group
Placebo

Outcomes
Primary outcome [1] 324786 0
Breathing response to 5 min hypoxia (i.e., peripheral chemoreflex) will be assess using a heated pneumotach attached to a mouth piece. Participants will be exposed to a gas mixture containing 10% O2 in nitrogen during this assessment
Timepoint [1] 324786 0
At baseline and at 4 weeks follow-up
Primary outcome [2] 324787 0
Blood pressure control. Brachial blood pressure will be measured with a clinically validated automated sphygmomanometer (Omron), using a cuff wrapped around the upper arm. Beat-to-beat BP will be measured using finger photoplethysmography, using a small lightweight cuff wrapped around the finger.
Timepoint [2] 324787 0
Baseline and at 4 week follow-up
Secondary outcome [1] 385746 0
Venous compliance will be quantified using high-resolution Doppler ultrasound (uSmart 3300, Terason) coupled with automated edge detection and wall tracking of arterial images. Lower limb vein diameter will measured during progressive thigh cuff inflation and deflation
Timepoint [1] 385746 0
Baseline and 4 week follow up
Secondary outcome [2] 387003 0
Muscle sympathetic nerve activity (SNA), Muscle SNA will be measured using a small, sterile wire (unipolar tungsten microelectrodes, tip measuring 1-5 um) inserted near the fibular head on the outside of the leg using published techniques.
Timepoint [2] 387003 0
Baseline Baseline and 4 week follow up

Eligibility
Key inclusion criteria
-Patients with essential hypertension (At least Stage 2 hypertension; untreated office SBP greater or equal to 140 mmHg or DBP greater or equal to 90 mmHg);
-Men and women;
-Aged over 18 years;
-Body mass index <35 kg/m2
Minimum age
18 Years
Maximum age
85 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
-Significant arrhythmias (e.g., atrial fibrillation, previous VT / significant ventricular ectopy)
-Hemodynamically significant valvular heart disease (e.g., stenosis, mechanical valve replacement)
-Severe left ventricular systolic dysfunction
-Recent acute coronary syndrome (<12 months) (e.g., MI, angioplasty, unstable angina)
-Previous coronary artery bypass surgery
-Secondary causes of hypertension (e.g., phaeochromocytoma)
-Recent stroke/TIA (<12 months)
-Current smoker
-Body mass index <18 kg/m2.
-Current pregnancy
-Current user of recreational drugs
-Current abuser of alcohol
-Inability to fully or appropriately provide consent (e.g., language issue, reading capability)
-Underlying medical conditions, which in the opinion of the Investigator place the participant at unacceptably high risk for participating in the study.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Phase 4
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Stopped early
Data analysis
Data analysis is complete
Reason for early stopping/withdrawal
Lack of funding/staff/facilities
Date of first participant enrolment
Anticipated
2/03/2022
Actual
18/05/2022
Date of last participant enrolment
Anticipated
28/10/2022
Actual
22/02/2023
Date of last data collection
Anticipated
30/11/2022
Actual
10/03/2023
Sample size
Target
80
Accrual to date
Final
61
Recruitment outside Australia
Country [1] 22856 0
New Zealand
State/province [1] 22856 0

Funding & Sponsors
Funding source category [1] 306468 0
University
Name [1] 306468 0
University of Auckland
Country [1] 306468 0
New Zealand
Primary sponsor type
University
Name
University of Auckland
Address
85 Park Road, Grafton
Auckland 1010
Country
New Zealand
Secondary sponsor category [1] 306995 0
None
Name [1] 306995 0
Address [1] 306995 0
Country [1] 306995 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 306676 0
Northern A Health and Disability Ethics Committe
Ethics committee address [1] 306676 0
Ethics committee country [1] 306676 0
New Zealand
Date submitted for ethics approval [1] 306676 0
Approval date [1] 306676 0
01/06/2020
Ethics approval number [1] 306676 0
20/NTA/29

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 104634 0
A/Prof James Fisher
Address 104634 0
University of Auckland 85 Park Road, Grafton Auckland 1023
Country 104634 0
New Zealand
Phone 104634 0
+640212968936
Fax 104634 0
Email 104634 0
[email protected]
Contact person for public queries
Name 104635 0
Mickey Fan
Address 104635 0
University of Auckland 85 Park Road, Grafton Auckland 1023
Country 104635 0
New Zealand
Phone 104635 0
+640212968936
Fax 104635 0
Email 104635 0
[email protected]
Contact person for scientific queries
Name 104636 0
James Fisher
Address 104636 0
University of Auckland 85 Park Road, Grafton Auckland 1023
Country 104636 0
New Zealand
Phone 104636 0
+640212968936
Fax 104636 0
Email 104636 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
Yes
Will there be any conditions when requesting access to individual participant data?
Persons/groups eligible to request access:
• Researchers whom have directly requested

Conditions for requesting access:
• -

What individual participant data might be shared?
• Basic de-identified participant characteristics, resting blood pressure values

What types of analyses could be done with individual participant data?
• meta-analysis

When can requests for individual participant data be made (start and end dates)?
From:
start date: 01/10/2022
end date: 01/10/2024

To:
-

Where can requests to access individual participant data be made, or data be obtained directly?
• Direct email contact ([email protected])

Are there extra considerations when requesting access to individual participant data?
No


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
9347Study protocol    Study-related document.docx
9348Ethical approval    Study-related document.pdf



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.