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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
A Cluster Randomised controlled trial of an Automated versus manual device for Blood pressure management.
Scientific title
A cluster randomised controlled trial of the effect of general practitioner blood pressure measurement of all patients aged 18 years or over who present during the study week, using automated or manual blood pressure device on digit preference, number of measurements (overall and per individual), prescribing of antihypertensive medications, dose adjustments, and mean systolic and diastolic blood pressure.
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Blood pressure measurement 1575 0
Condition category
Condition code
Public Health 1677 1677 0 0
Health service research

Study type
Description of intervention(s) / exposure
GP participants in practices randomised to receive automated blood pressure measuring device, the OMRON HEM-907 in all clinical rooms.
The duration of the intervention will be one week after an initial 1 week run-in phase.
Blood pressure recordings of all patients aged 18 years or more and hypertension management (where relevant) is determined by research nurses auditing clinical records once after the trial week.
Both the number and level of blood pressure is determined by searching electronic and paper clinical records of the patient for the study week and recording each on an audit sheet.
Intervention code [1] 1433 0
Diagnosis / Prognosis
Comparator / control treatment
GP participants in practices randomised to control will use usual practice.
Control group

Primary outcome [1] 2323 0
Digital preference in blood pressure recordings (1mmHg tolerance in automated devices, 2mmHg in manual).
Timepoint [1] 2323 0
Audit of clinical record once after the study week.
Secondary outcome [1] 4051 0
BP recordings made overall and per individual
Timepoint [1] 4051 0
Audit of clinical record once after the study week.
Secondary outcome [2] 4052 0
prescriptions of antihypertensive medications
Timepoint [2] 4052 0
Audit of clinical record once after the study week.
Secondary outcome [3] 4053 0
dose adjustments of antihypertensive medications
Timepoint [3] 4053 0
Audit of clinical record once after the study week.
Secondary outcome [4] 4054 0
Mean of systolic blood pressure recordings
Timepoint [4] 4054 0
Audit of clinical record once after the study week.
Secondary outcome [5] 4055 0
Mean of diastolic blood pressure recordings
Timepoint [5] 4055 0
Audit of clinical record once after the study week.

Key inclusion criteria
Inclusion criteria: General practices where at least one registered and practicing general practitioner has signed informed consent.
Minimum age
18 Years
Maximum age
Not stated
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Exclusion criteria. General practices where automated blood pressure devices are currently used.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central cluster randomisation of general practices.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by using a randomization table created by a computer software
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Phase 4
Type of endpoint(s)
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)

Funding & Sponsors
Funding source category [1] 1823 0
Name [1] 1823 0
High Blood Pressure Research Council of Australia
Address [1] 1823 0
4/184 Main Street
Country [1] 1823 0
Primary sponsor type
Menzies Research Institute
Private Bag 33
Hobart TAS 7001
Secondary sponsor category [1] 1643 0
Name [1] 1643 0
Address [1] 1643 0
Country [1] 1643 0

Ethics approval
Ethics application status
Ethics committee name [1] 3410 0
Tasmanian Health and Medical Human Research Ethics Committee
Ethics committee address [1] 3410 0
Ethics committee country [1] 3410 0
Date submitted for ethics approval [1] 3410 0
Approval date [1] 3410 0
Ethics approval number [1] 3410 0

Brief summary
Hypertension is the commonest problem managed in general practice. In this setting as in others control remains less than ideal. As there is a linear relationship between blood pressure level and risk of death any change in standard management that leads to improved blood pressure control is likely to be beneficial.
CRAB will compare the measurement and management of sequential adults attending a general practice over a week. It will use the endpoints of digital preference, the number of individuals who have a blood pressure measurement, the number of measurements an individual has, mean systolic and diastolic blood pressure, and drug management where hypertension is treated. It is a trial of clinical effectiveness in general practice where the majority of hypertension is managed.
This study will provide evidence for the potential changes in blood pressure recording and hypertension management of the introduction of new devices not containing mercury which are inevitable due to occupational health and safety concerns of this toxic material. The OMRON HEM-907 device is a validated blood pressure measurement device. We hypothesize that the use of automated measurement devices will increase the number of people who have a blood pressure measurement, the number of recordings per individual and will improve the management of individuals with hypertension.
Trial website
Trial related presentations / publications
Nelson MR, Winzenberg T. A cluster randomised controlled trial of an automated versus manual device for blood pressure management (CRAB). Hypertension (Volume 49, Number 6, June 2007).
Public notes

Principal investigator
Name 27367 0
Address 27367 0
Country 27367 0
Phone 27367 0
Fax 27367 0
Email 27367 0
Contact person for public queries
Name 10622 0
Mark Nelson
Address 10622 0
Menzies Research Institute
Private Bag 33
43 Collins St
Hobart TAS 7001
Country 10622 0
Phone 10622 0
+61 3 62264734
Fax 10622 0
+61 3 62264770
Email 10622 0
Contact person for scientific queries
Name 1550 0
Mark Nelson
Address 1550 0
Menzies Research Institute
Private Bag 33
43 Collins St
Hobart TAS 7001
Country 1550 0
Phone 1550 0
+61 3 62264734
Fax 1550 0
+61 3 62264770
Email 1550 0

No information has been provided regarding IPD availability
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