HypertensionNCT03762304
The Effect of Household-based Screening on Blood Pressure Changes in South Africa
An observational study of Hypertension and Blood Pressure, run by Till Bärnighausen.
Trial summary
This study will evaluate the effect of household-based screening and care encouragement for blood pressure on subsequent changes in blood pressure. The study uses a quasi-experimental regression discontinuity design with existing population-based secondary data from the 2008, 2010, 2012, 2014, and 2017 waves of the… Read more about this study
- Who is it for?
- Ages 30 years and older
- Conditions the study is for
- Hypertension, Blood Pressure
- What is being tested?
- Household blood pressure screening with care encouragement
- How many people
- 3,986 participants
- Where
- No sites listed yet
- Study dates
- Feb 2008to Dec 2017
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 30 years and older
- All sexes
- Adult, Older adult
Study population: Individuals will be drawn from the 2008, 2010, 2012, and 2014 waves of the National Income Dynamics Study (NIDS) with the 2017 wave used only for follow-up. The NIDS is a nationally representative, household-based, survey of families and individuals from across South Africa.
Who may be able to join
- Age greater than or equal to 30
- Valid blood pressure measurements
Who cannot join
- Prior diagnosis of hypertension
- Currently taking medication for blood pressure
- Measured with a blood pressure above 140 mmHg systolic or 90 mmHg diastolic in a previous wave of data
About this study
Official title: The Effect of Household-based Screening on Blood Pressure Changes in South Africa: a Regression Discontinuity Study
This study will evaluate the effect of household-based screening and care encouragement for blood pressure on subsequent changes in blood pressure. The study uses a quasi-experimental regression discontinuity design with existing population-based secondary data from the 2008, 2010, 2012, 2014, and 2017 waves of the National Income Dynamics Study in South Africa.
Read the detailed description
Household-based screening and referral to care for blood pressure may improve blood pressure control at the population level in many low- and middle-income countries.
This observational study will use a quasi-experimental regression discontinuity design to evaluate the effect of household-based screening for blood pressure with care encouragement for potentially hypertensive individuals on subsequent changes in blood pressure over time.
Individuals had their blood pressure measured in the household as part of the National Income Dynamics Study data collection. If individuals had a measured blood pressure in the hypertensive zone, they were told that they had elevated blood pressure, that high blood pressure can lead to life threatening consequences, and that they should seek further care. The study exploits the fact that individuals were given this information based on a hard blood pressure cutoff. Therefore, the investigators will evaluate the causal effect of this household-based intervention in the absence of randomization by comparing individuals with a baseline blood pressure just above and below the cut off.
- Conditions
- Hypertension, Blood Pressure
- Being tested
- Household blood pressure screening with care encouragement
- Keywords
- Causal inference, Regression discontinuity
- Medical subject headings
- Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Household blood pressure screening with care encouragementOther
During the household survey visit, survey enumerators collected two measurements of the respondent's blood pressure. If either of the measurements exceeded 140 mmHg systolic or 90 mmHg diastolic, enumerators told participants: "Your blood pressure readings are higher than normal. High blood pressure is dangerous because it makes the heart work too hard. High blood pressure increases the risk of heart disease and stroke. High blood pressure can also cause other problems, such as heart failure, kidney disease, and blindness. You can control high blood pressure by taking action." Then the enumerators recommend that an individual seek medical care within 2 months.
| Study group | Role | What they receive |
|---|---|---|
| Intervention group | The intervention group consists of individuals with a measured blood pressure just above the hypertensive cut-off of 140 mmHg systolic or 90 mmHg diastolic blood pressure who have never previously been diagnosed as hypertensive and are not taking medication to lower their blood pressure. The exact upper bound on blood pressure will be determined empirically. Individuals in the intervention group were told that that their blood pressure was high, that high blood pressure can lead to life threatening consequences, that blood pressure control can reduce these negative consequences, and that they should seek follow-up care for their blood pressure. Receives: Other: Household blood pressure screening with care encouragement | |
| Control group | The control group consists of individuals with a measured blood pressure just below the hypertensive cut-off of 140 mmHg systolic and 90 mmHg diastolic blood pressure who have never previously been diagnosed as hypertensive and are not taking medication to lower their blood pressure. The exact lower bound on blood pressure will be determined empirically. These individuals were not given the care encouragement intervention. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Two-year change in systolic blood pressure
For each survey wave, blood pressure is measured at the household by a trained enumerator using an electronic blood pressure device. The enumerators take two separate measurements during the course of the visit with at least three minutes between measurements with individuals in a seated position. The investigators will take the average of the two systolic blood pressure measurements as their main outcome measure.
Measured: Approximately two years based on the difference between survey waves in the years 2008, 2010, 2012, 2014, and 2017
Nine-year change in systolic blood pressure
For each survey wave, blood pressure is measured at the household by a trained enumerator using an electronic blood pressure device. The enumerators take two separate measurements during the course of the visit with at least three minutes between measurements with individuals in a seated position. The investigators will take the average of the two systolic blood pressure measurements as their main outcome measure.
Measured: Baseline in 2008 and approximately nine years later in 2017.
Secondary outcomes (2)
Health-seeking behavior
Health-care utilization is measured at the household based on respondents' answer to the survey question: "When did you last consult someone about your health?"
Measured: Cross-sectionally in 2010, 2012, 2014, and 2018
Blood pressure treatment
Whether an individual is currently taking treatment to control their blood pressure is measured during the household survey based on the answer to the question: "Are you currently taking medicine for high blood pressure?"
Measured: Cross-sectionally in 2010, 2012, 2014, and 2018
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Dec 2018
- Study startFeb 2008
- Primary completionDec 2017
- Study completionDec 2017
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HypertensionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Prospective
- Enrolment
- 3,986 participants (actual)
Sponsor and investigators
- Lead sponsor
- Till Bärnighausen
- Sponsor type
- University, hospital or other
- Collaborators
- Emory University
- Responsible party
- Sponsor-investigator, Till Bärnighausen, University Hospital Heidelberg
- Investigators
- Nikkil Sudharsanan, PhD, Principal investigator, Research group leader
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03762304
- Sponsor's protocol ID
- RDD - BP - South Africa
- Status last verified
- Dec 2018
- First submitted
- 30 Nov 2018
- Last updated
- 7 Dec 2018
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The data are already publicly available at: http://www.nids.uct.ac.za/nids-data/data-access
Study at a glance
From the registry record, last updated by the sponsor on 7 Dec 2018. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Household-based Screening on Blood Pressure Changes in South Africa: a Regression Discontinuity Study
- ClinicalTrials.gov ID
- NCT03762304
- Acronym / sponsor ID
- RDD - BP - South Africa
- Conditions
- Hypertension, Blood Pressure
- Keywords
- Causal inference, Regression discontinuity
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 3,986 participants (actual)
- Lead sponsor
- Till BärnighausenUniversity, hospital or other
- Collaborators
- Emory University
- Study start
- Feb 2008 (actual)
- Primary completion
- Dec 2017 (actual)
- Study completion
- Dec 2017 (actual)
- First posted
- 3 Dec 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study will evaluate the effect of household-based screening and care encouragement for blood pressure on subsequent changes in blood pressure. The study uses a quasi-experimental regression discontinuity design with existing population-based secondary data from the 2008, 2010, 2012, 2014, and 2017 waves of the National Income Dynamics Study in South Africa.
Detailed description
Household-based screening and referral to care for blood pressure may improve blood pressure control at the population level in many low- and middle-income countries.
This observational study will use a quasi-experimental regression discontinuity design to evaluate the effect of household-based screening for blood pressure with care encouragement for potentially hypertensive individuals on subsequent changes in blood pressure over time.
Individuals had their blood pressure measured in the household as part of the National Income Dynamics Study data collection. If individuals had a measured blood pressure in the hypertensive zone, they were told that they had elevated blood pressure, that high blood pressure can lead to life threatening consequences, and that they should seek further care. The study exploits the fact that individuals were given this information based on a hard blood pressure cutoff. Therefore, the investigators will evaluate the causal effect of this household-based intervention in the absence of randomization by comparing individuals with a baseline blood pressure just above and below the cut off.
Study design
- Observational model
- Other
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Intervention group | – | Other: Household blood pressure screening with care encouragementThe intervention group consists of individuals with a measured blood pressure just above the hypertensive cut-off of 140 mmHg systolic or 90 mmHg diastolic blood pressure who have never previously been diagnosed as hypertensive and are not taking medication to lower their blood pressure. The exact upper bound on blood pressure will be determined empirically. Individuals in the intervention group were told that that their blood pressure was high, that high blood pressure can lead to life threatening consequences, that blood pressure control can reduce these negative consequences, and that they should seek follow-up care for their blood pressure. |
| Control group | – | –The control group consists of individuals with a measured blood pressure just below the hypertensive cut-off of 140 mmHg systolic and 90 mmHg diastolic blood pressure who have never previously been diagnosed as hypertensive and are not taking medication to lower their blood pressure. The exact lower bound on blood pressure will be determined empirically. These individuals were not given the care encouragement intervention. |
Who may qualify
- Ages
- 30 years and older
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Individuals will be drawn from the 2008, 2010, 2012, and 2014 waves of the National Income Dynamics Study (NIDS) with the 2017 wave used only for follow-up. The NIDS is a nationally representative, household-based, survey of families and individuals from across South Africa.
Key inclusion criteria (2 listed)
- Age greater than or equal to 30
- Valid blood pressure measurements
Key exclusion criteria (3 listed)
- Prior diagnosis of hypertension
- Currently taking medication for blood pressure
- Measured with a blood pressure above 140 mmHg systolic or 90 mmHg diastolic in a previous wave of data
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Household blood pressure screening with care encouragementDuring the household survey visit, survey enumerators collected two measurements of the respondent's blood pressure. If either of the measurements exceeded 140 mmHg systolic or 90 mmHg diastolic, enumerators told participants: "Your blood pressure readings are higher than normal. High blood pressure is dangerous because it makes the heart work too hard. High blood pressure increases the risk of heart disease and stroke. High blood pressure can also cause other problems, such as heart failure, kidney disease, and blindness. You can control high blood pressure by taking action." Then the enumerators recommend that an individual seek medical care within 2 months. | Other | Intervention group |
Primary outcome
Two-year change in systolic blood pressure
Time frame: Approximately two years based on the difference between survey waves in the years 2008, 2010, 2012, 2014, and 2017
For each survey wave, blood pressure is measured at the household by a trained enumerator using an electronic blood pressure device. The enumerators take two separate measurements during the course of the visit with at least three minutes between measurements with individuals in a seated position. The investigators will take the average of the two systolic blood pressure measurements as their main outcome measure.
Nine-year change in systolic blood pressure
Time frame: Baseline in 2008 and approximately nine years later in 2017.
For each survey wave, blood pressure is measured at the household by a trained enumerator using an electronic blood pressure device. The enumerators take two separate measurements during the course of the visit with at least three minutes between measurements with individuals in a seated position. The investigators will take the average of the two systolic blood pressure measurements as their main outcome measure.
2 secondary outcomes
Health-seeking behavior
Time frame: Cross-sectionally in 2010, 2012, 2014, and 2018
Blood pressure treatment
Time frame: Cross-sectionally in 2010, 2012, 2014, and 2018
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Dec 2018.
- Individual participant dataSharing planned: Yes. The data are already publicly available at: http://www.nids.uct.ac.za/nids-data/data-access
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Nikkil Sudharsanan, PhD principal investigator
Research group leader
Questions about this trial
What is this clinical trial studying?
An observational study of Hypertension and Blood Pressure, run by Till Bärnighausen.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Dec 2018. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Two-year change in systolic blood pressure (time frame: Approximately two years based on the difference between survey waves in the years 2008, 2010, 2012, 2014, and 2017). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Dec 2018.