ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12618001110279

Ethics application status

Approved

Date submitted

22/06/2018

Date registered

4/07/2018

Date last updated

11/02/2021

Date data sharing statement initially provided

9/01/2019

Type of registration

Prospectively registered

Titles & IDs

Public title

Identification of adults with true high blood pressure resistant to drugs and its relationship with breath pauses during sleep.

Scientific title

The prevalence of true resistant hypertension in Dunedin based adults with resistant hypertension and the association between true resistant hypertension and obstructive sleep apnoea risk.

Secondary ID [1]

None

Universal Trial Number (UTN)

U1111-1215-4535

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Resistant hypertension

Obstructive sleep apnoea

Condition category

Condition code

Cardiovascular

Hypertension

Respiratory

Sleep apnoea

Intervention/exposure

Study type

Observational

Patient registry

False

Target follow-up duration

Target follow-up type

Description of intervention(s) / exposure

This study is an observational study which aims to: 1) identify individuals with true resistant hypertension (TRHT) in a population of Dunedin based adults 60 years and younger, with resistant hypertension (RHT) as defined under the current guidelines (2017) of the American Heart Association and American College of Cardiology; 2) investigate the association between TRHT and high risk of obstructive sleep apnoea (OSA) in the sub group of individuals with TRHT.
Dunedin based adults, 60 years or younger, who meet the criteria for RHT (are on three or more pharmacological agents of different classes, including a diuretic), have been identified from the Ministry of Health Pharmaceutical Collection Warehouse (PCW) database.

Following a briefing by researchers about the study at a scheduled meeting of the local General Practitioners Association, researchers will gain agreement from General Practitioners to distribute a letter to patients. A letter of invitation to participate in the study will be co-signed by Dr. Skinner and Associate Professor Wilkins. Letters will then be distributed to General Practitioners, who will be asked to forward copies to their patients identified from the PCW database.

Step I – Initial recruitment
Potential participants will be invited to contact Dr Skinner with enquiries and to indicate their interest in participating in the study. The Principal investigator (PI), the PhD candidate, will provide each participant with an appointment time for the initial assessment where written informed consent will be obtained first. The session will be at the School of Physiotherapy.

Step II – Assessment and measurements
Appointment 1:
The PI will obtain the participant’s demographic data (age; gender; ethnicity); general health and habits, physical activity level, quality of life (SF-36) and OSA risk (ESS), using self-administered questionnaires. Participants will use a tablet computer to complete this section which will take approximately 20 minutes. Data will then be downloaded onto the study database (MS Excel).

The PI will then take the participant’s resting blood pressure (office blood pressure – (BP)), heart rate, and peripheral saturation using standardised, calibrated equipment (NT1A Pulse oximeter, New Tech, Hamburg, Germany and Omron automatic digital blood pressure monitor, HEM 7322, Netherlands) and in accordance with the ACC/AHA 2017 guidelines. Next, the PI will take the anthropometric (body weight, height and circumferences of neck, waist, hip,) measurements of the participant using standard guidelines and equipment; electronic weighing scale (kg) and stadiometer (cm), measuring tape (scale in cm); with two decimal point accuracy. The equipment will be calibrated as required. This section of the procedure will take about 15 minutes. The variables, body mass index (BMI) and waist to hip ratio will be calculated using simple formulas on MS Excel.

The subset with RHT who also score above or equal 9 on the Epworth Sleepiness Scale (ESS) will be identified as ‘at risk for OSA’, and will be fitted with 24h ambulatory blood pressure monitor on the non-dominant upper arm, at the Cardiology Research Laboratory, on 9th floor in Dunedin Hospital. The participant will be advised to undertake daily activities/sleep as usual over the next 24 hours.

Appointment 2:
On the following day, the device will be removed at the same setting, the Cardiology Research Laboratory, and data downloaded to confirm TRHT or not. Where THRT is confirmed the participant will have an echocardiogram to confirm baseline left ventricular function (results to be interpreted by co-investigator cardiologist).

After the echocardiogram, the PI will conduct a Six Minute Walk Test (6MWT) following the standardised test and safety procedures. Then an activity monitor (ActiGraph GT3XPB, Pensacola, Florida) will be calibrated and placed on the non-dominant wrist to be worn for seven days/nights to determine the participant’s true levels of functional activity during the day and during sleep. The participants will select the most convenient way to return the Activitrax monitor, either in person or by post. Data will be downloaded and analysed for activity levels, and sleep parameters, by the PI. Objective measurements of daytime activity (step count, time in low/moderate/vigorous physical activity, sedentary time and sleep, including total sleep time, awakenings, average awakenings, sleep efficiency, sleep onset, latency and wake after sleep onset) will be derived from the Actigraph calculator for the period.

The PI who will then determine the correlation between Epworth Sleepiness Scale score and sleep fragmentation and subsequently identify those with high risk of OSA in the subset with TRHT.

Note: Participants not found to have TRHT will meet with the co-investigator (Primary Supervisor) to discuss the outcomes and will be advised to visit their GP to discuss the report on findings for 24hABPM, risk of OSA (obtained from the questionnaire, ESS above or equal to 9), and self-reported physical activity level). The participants with objective signs of OSA scored from the data downloaded from the activity monitor but not with TRHT will be referred by the co-investigator cardiologist, to the physician at the Sleep Clinic for further sleep analysis.

Individuals who have TRHT and high risk of OSA will be invited to participate in a second study: a feasibility study to investigate the outcomes of a supervised physical activity programme on blood pressure levels.

Intervention code [1]

Diagnosis / Prognosis

Intervention code [2]

Early Detection / Screening

Comparator / control treatment

No control group

Control group

Uncontrolled

Outcomes

Primary outcome [1]

The primary outcome is the prevalence of TRHT. TRHT will be assessed using 24h ambulatory blood pressure monitoring, in Dunedin based population of adults with resistant hypertension

Timepoint [1]

24h from the appointment 1

Primary outcome [2]

The positive association between participants with TRHT and the high risk of OSA

Timepoint [2]

One week following appointment 2

Secondary outcome [1]

Correlation between increased Epworth Sleepiness Scale score and sleep fragmentation using the sleep/wake data downloaded by the actigraphy monitoring .

Timepoint [1]

One week from the appointment 2

Secondary outcome [2]

cardio respiratory fitness will be gauged by the six minute walk test, using a 30 meter indoor walking track, of the population with TRHT and high risk of OSA.

Timepoint [2]

One week from the appointment 2

Secondary outcome [3]

Physical activity level will be measured from activity level captured over seven days and downloaded from the Actigraph monitor; daily amounts, frequency and levels of activity will be determined for each of seven days, of the population with TRHT and high risk of OSA. (This is a composite secondary outcome)

Timepoint [3]

One week from the appointment 2

Secondary outcome [4]

Structural and functional features of the heart - size and shape of the heart pumping capacity, and the location and extent of any tissue damage and estimates of heart function (cardiac output and ejection fraction), will be described from the results of two dimensional electrocardiography, of the population with TRHT and high risk of OSA. (This is a composite secondary outcome)

Timepoint [4]

On the day of appointment 2

Eligibility

Key inclusion criteria

Age: 18-60 years inclusive
Gender: all
Able to communicate/follow instructions in English
Based in Dunedin region
Diagnosed with hypertension
Prescribed three of more antihypertensive medications including a diuretic (RHT Definition).

Minimum age

18 Years

Maximum age

60 Years

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

Diagnosed with hypertension prescribed two or less antihypertensive medications
Adults above the age of 60 years
Diagnosed/known renal disease
Females who are pregnant

Study design

Purpose

Screening

Duration

Cross-sectional

Selection

Defined population

Timing

Prospective

Statistical methods / analysis

The sample sizes have been determined based on the Dunedin based adult population (559), aged below 60 years, diagnosed with hypertension and prescribed three or more medications who can be considered to have RHT. For the descriptive study the estimated sample size is n=33 (estimated using the 10% prevalence and 10% margin of error). For study II the minimum number of participants required to detect 5 mmHg differences blood pressure with standard deviation 6 mmHg is n=14 at significance level 5% and 80% power.

Simple statistics (mean, standard deviation, range) will be used to describe the demographic data and the measurements (anthropometry, blood pressure, sleep, activity, cardiac parameters) of the population with RHT in Dunedin region and in the subpopulation with TRHT and high risk of OSA. The data for anthropometrics, blood pressure, activity and cardiac parameters will be compared with accepted international guidelines, and questionnaires will be interpreted using standard descriptors.

The relationship between the anthropometry parameters, blood pressure, ESS score, cardiorespiratory fitness, and activity and sleep levels with TRHT will be determined using regression analysis.

The statistical package for social sciences (SPSS) version 25.0 or above for Windows (IBM SPSS version 25.0 or above), NY, USA will be used for the data analysis.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

1/02/2019

Actual

25/03/2019

Date of last participant enrolment

Anticipated

1/08/2019

Actual

5/02/2020

Date of last data collection

Anticipated

1/09/2019

Actual

13/02/2020

Sample size

Target

Accrual to date

Final

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Dunedin/ Otago

Funding & Sponsors

Funding source category [1]

University

Name [1]

School of physiotherapy, University of Otago

Address [1]

325,Great King Street, Dunedin North (9016)

Country [1]

New Zealand

Primary sponsor type

Individual

Name

Dr. Margot Skinner

Address

School of Physiotherapy, University of Otago,
325, Great King Street,
Dunedin North. 9016

Country

New Zealand

Secondary sponsor category [1]

Individual

Name [1]

Suranga Dassanayake

Address [1]

School of Physiotherapy, University of Otago,
325, Great King Street,
Dunedin North 9016

Country [1]

New Zealand

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Health and Disability Ethics Commitee

Ethics committee address [1]

Postal address:
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

13/07/2018

Approval date [1]

10/09/2018

Ethics approval number [1]

18/CEN/141

Summary

Brief summary

High blood pressure (BP) or hypertension (HT) is a worldwide problem. BP which is difficult to maintain using three or more BP medications is defined as resistant hypertension (RHT). The exact global prevalence of RHT is unknown but it has been estimated to be 20-30% of the population with HT. 24 hour BP monitoring (24h Ambulatory Blood Pressure Monitoring - 24ABPM) is recommended to exclude the potential for a false reading of BP in the clinical settings and thereby to diagnose true RHT (TRHT). Cardiovascular disease is the greatest cause of morbidity and mortality in New Zealand and the prevalence of HT in the adult population is over 30%, with ethnic disparities. The most common form of sleep disordered breathing, obstructive sleep apnoea (OSA), has a strong relationship with uncontrolled RHT and research indicates that both conditions enhance each other.
The hypotheses of the designed study are; 1) In Dunedin based individuals aged 60 years and below, diagnosed with RHT, 24h ABPM will identify a subgroup with TRHT; 2) There is correlation between Epworth Sleepiness Scale (ESS) score and levels of sleep fragmentation in the subgroup of individuals with TRHT; 3)There is an association between TRHT and high risk of OSA, in the subgroup of individuals.

The population has been identified from the Ministry of Health Pharmaceutical Collection Warehouse. Consenting adults will complete health, OSA risk and activity questionnaires. The subset with RHT and OSA risk will have 24h ABPM to confirm TRHT, anthropometric measurements, cardiorespiratory fitness, echocardiogram, sleep and activity monitoring for seven days and nights. Sleep outcomes and ESS score will be used to confirm the level of risk of OSA. 

The aims of the study are to: 1) identify individuals with TRHT in a population of Dunedin based adults 60 years and younger, with RHT as defined under the current guidelines (2017) of the American Heart Association and American College of Cardiology; 2) investigate the association between TRHT and high risk of OSA in the sub group of individuals with TRHT.

The objectives are; to determine the prevalence of TRHT measured by 24h ABPM in Dunedin based individuals with RHT; to investigate the relationship between ESS scores and sleep fragmentation in the Dunedin based individuals identified TRHT; to investigate the association between TRHT and high risk of OSA, in the Dunedin based individuals.

The outcomes of the study will be; The prevalence of TRHT in a population with RHT and its association with high risk of OSA and the correlation between increased ESS score and sleep fragmentation in the subset with TRHT.

The investigators will adhere to the new guideline for HT and include only those with TRHT which leads to creating a new knowledge dimension. The findings have potential to change the direction of research in the area, open the topic of TRHT to more debate and support modified guidelines for physicians and physiotherapists in managing.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Mr Suranga Dassanayake

Address

School of Physiotherapy, University of Otago,
325, Great King Street
Dunedin North 9016.

Country

New Zealand

Phone

+64 224976151

Fax

suranga.dassanayake@postgrad.otago.ac.nz

Contact person for public queries

Name

Suranga Dassanayake

Address

School of Physiotherapy, University of Otago,
325, Great King Street
Dunedin North 9016.

Country

New Zealand

Phone

+64 224976151

Fax

suranga.dassanayake@postgrad.otago.ac.nz

Contact person for scientific queries

Name

Margot Skinner

Address

School of Physiotherapy, University of Otago,
325, Great King Street
Dunedin North 9016.

Country

New Zealand

Phone

+64 34797466

Fax

margot.skinner@otago.ac.nz

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

No/undecided IPD sharing reason/comment

The individual data for the study will be available but not will be shared with any other research or with another party. Only the study investegators will be able to access data. The data will be kept for 4 years according to the regulations.

What supporting documents are/will be available?

Doc. No.	Type	Attachment
972	Ethical approval	375298-(Uploaded-08-01-2019-16-43-40)-Study-related document.pdf
10613	Study protocol	375298-(Uploaded-27-07-2020-08-26-37)-Study-related document.pdf
10614	Informed consent form	375298-(Uploaded-27-07-2020-08-33-31)-Study-related document.docx

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	The prevalence of individuals at high risk of true resistant hypertension and obstructive sleep apnoea in a New Zealand cohort.	2021

N.B. These documents automatically identified may not have been verified by the study sponsor.

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