Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12608000041358
Ethics application status
Approved
Date submitted
22/01/2008
Date registered
23/01/2008
Date last updated
16/01/2013
Type of registration
Retrospectively registered

Titles & IDs
Public title
A study to determine the clinical value of measuring central blood pressure in patients with hypertension
Scientific title
A randomised study to determine the value of central Blood Pressure for GUIDing managEment of hypertension (BP GUIDE Study)
Secondary ID [1] 252895 0
N/A
Universal Trial Number (UTN)
Trial acronym
BP GUIDE Study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Essential hypertension 2743 0
Condition category
Condition code
Cardiovascular 2883 2883 0 0
Hypertension

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Patients with essential hypertension treated by their General Practitioners will be randomised to have treatment decisions (i.e. titration of antihypertensive therapy) based on central blood pressure measures (intervention) versus usual care (control). Central blood pressure will be measured non invasively by radial tonometry using commercial equipment. The duration of intervention is 12 months. All participants will be receiving oral antihypertensive medication upon entry to the study as part of their usual medical care. The dose and frequency of drug administration at study entry will be at the discretion of each participants attending General Practitioner. Recommendations about changing antihypertensive therapy (maintain, decrease or increase medication) will be made throughout the course of the study. These recommendations will be made on the basis of central or brachial blood pressure and the clinical presentation of each individual participant. Recommendations will be provided to each participants attending General Practitioner (there is no standard dose).

A data and safety monitoring committee has not been appointed because we have determined the study to be extremely low risk. Indeed, 1768 patients would be required in each group in order to detect a significant change in 2D LV mass over the course of one year (p=0.001 and 80% power). These calculations are based on an expected change in LV mass of 4.747 g per year, with a standard deviation of 35 at baseline and 37 at one year, as per Framingham data (Lieb W et al. Circ. 2009; 119:3085-3092).
Intervention code [1] 2495 0
Treatment: Other
Comparator / control treatment
The control treatment refers to usual care of patients with essential hypertension. In other words, treatment decisions about antihypertensive therapy will be guided by blood pressure measures from the upper arm (as well as clinical presentation).
Control group
Active

Outcomes
Primary outcome [1] 3754 0
The change in left ventricular mass assessed by real time three dimensional echocardiography
Timepoint [1] 3754 0
Baseline and 12 months
Primary outcome [2] 3755 0
Quality of life assessed by SF36 (short form 36) questionnaire with the addition of the Hypertension specific questionnaire.
Timepoint [2] 3755 0
Baseline and 12 months
Primary outcome [3] 3756 0
Medication useage assessed by daily defined doseage
Timepoint [3] 3756 0
Baseline, 3, 6, 9 and 12 months
Secondary outcome [1] 6342 0
Exercise central blood pressure (assessed by radial applanation tonometry during light bicycle exercise)
Timepoint [1] 6342 0
Baseline and 12 months

Eligibility
Key inclusion criteria
Essential hypertension
Minimum age
18 Years
Maximum age
75 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Brachial blood pressure >180/100 mmHg. Taking more than 3 antihypertensive drugs. Clinical history of coronary artery disease. Clinical history of renal disease (or serum creatinine >140 umol). Left ventricular hypertrophy (>59 g/m2.7; women and >64 g/ m2.7; men). Secondary causes of hypertension. Aortic valve stenosis or upper limb obstructive atherosclerosis. Pregnant females.

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)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Stratified allocation based on age (> or < 60 years of age)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
16/10/2007
Actual
Date of last participant enrolment
Anticipated
Actual
12/07/2012
Date of last data collection
Anticipated
Actual
Sample size
Target
284
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 743 0
4102

Funding & Sponsors
Funding source category [1] 2999 0
Commercial sector/Industry
Name [1] 2999 0
AtCor Medical
Country [1] 2999 0
Australia
Funding source category [2] 3000 0
University
Name [2] 3000 0
The University of Queensland
Country [2] 3000 0
Australia
Funding source category [3] 243830 0
Government body
Name [3] 243830 0
NHMRC Project Grant
Country [3] 243830 0
Australia
Primary sponsor type
University
Name
The University of Queensland
Address
Department of Medicine
Princess Alexandra Hospital
Woolloongabba, QLD, 4102
Country
Australia
Secondary sponsor category [1] 2706 0
None
Name [1] 2706 0
Address [1] 2706 0
Country [1] 2706 0
Other collaborator category [1] 251604 0
Other
Name [1] 251604 0
Dr Walter Abhayaratna
Address [1] 251604 0
Canberra Hospital, Clinical Trials Unit, Canberra, ACT
Country [1] 251604 0
Australia
Other collaborator category [2] 251605 0
Hospital
Name [2] 251605 0
Dr Phillip Roberts-Thomson
Address [2] 251605 0
Royal Hobart Hospital/Menzies Research Institute
Cardiology Department
Hobart, TAS.
Country [2] 251605 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 4960 0
Princes Alexandra Hospital Human Research Ethics Committee
Ethics committee address [1] 4960 0
Health Services District
Princess Alexandra Hospital
Woolloongabba, QLD, 4102
Ethics committee country [1] 4960 0
Australia
Date submitted for ethics approval [1] 4960 0
Approval date [1] 4960 0
04/10/2008
Ethics approval number [1] 4960 0
2007/090

Summary
Brief summary
Hypertension is a major risk factor for cardiovascular disease and the most frequent problem managed by General Practitioners (GP’s) in Australia. Blood pressure is traditionally measured by inflating a cuff around the upper arm, and doctors rely on this information when making treatment decisions. However, individuals with the same, or similar, brachial blood pressure may have very different central blood pressure (>30 mmHg difference). This difference is important because central blood pressure has been shown to have greater relevance to the structure and function of the heart and arteries. Moreover, several longitudinal trials show that central blood pressure indices are independently associated with severe cardiovascular events and mortality.

When all these data are considered, relying solely on the measure of brachial blood pressure has severe limitations for assessing patient risk and determining the effect of treatment. Indeed, the evidence points toward an expectation that patient care will be improved by tailoring medical treatment based on central, rather than upper arm, blood pressure. However, there is no data to show that using central blood pressure changes decision-making or outcomes and, therefore, doctors continue to rely on brachial blood pressure to make therapeutic decisions. The technology is now available to measure central blood pressure non-invasively by radial applanation tonometry. This methodology should improve patient care by providing the treating clinician with a greater understanding of the “true” risk relating to blood pressure control and, therefore, make more appropriate treatment decisions.

This research program aims to bridge the gap between the current method of managing patients with hypertension (focus on upper arm blood pressure) and the theoretical improvement in the quality of patient care that may be achieved with the use of new technology and consideration of central blood pressure. The research should provide the foundation model for a new way to undertake management of patients with hypertension.

It is hypothesised that patients randomised to have treatment decisions based on central blood pressure will have no significant change in left ventricular mass; will have less use of medication and improved quality of life scores.
Trial website
Nil
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 28317 0
Dr James Sharman
Address 28317 0
Menzies Research Institute, University of Tasmania Private Bag 23 Hobart TAS 7001
Country 28317 0
Australia
Phone 28317 0
+61 3 6226 4709
Fax 28317 0
+61 3 6226 7755
Email 28317 0
James.Sharman@menzies.utas.edu.au
Contact person for public queries
Name 11474 0
Dr James Sharman
Address 11474 0
Menzies Research Institute, University of Tasmania Private Bag 23 Hobart TAS 7001
Country 11474 0
Australia
Phone 11474 0
+61 3 6226 4709
Fax 11474 0
+61 3 6226 7755
Email 11474 0
j.sharman@uq.edu.au
Contact person for scientific queries
Name 2402 0
Dr James Sharman
Address 2402 0
Menzies Research Institute,
University of Tasmania
Private Bag 23
Hobart TAS 7001
Country 2402 0
Australia
Phone 2402 0
+61 3 6226 4709
Fax 2402 0
+61 3 6226 7755
Email 2402 0
James.Sharman@menzies.utas.edu.au

No information has been provided regarding IPD availability


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

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

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseGuiding Hypertension Management Using Central Blood Pressure: Effect of Medication Withdrawal on Left Ventricular Function.2016https://dx.doi.org/10.1093/ajh/hpv108
N.B. These documents automatically identified may not have been verified by the study sponsor.