<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT03762304</url>
  </required_header>
  <id_info>
    <org_study_id>RDD - BP - South Africa</org_study_id>
    <nct_id>NCT03762304</nct_id>
  </id_info>
  <brief_title>The Effect of Household-based Screening on Blood Pressure Changes in South Africa</brief_title>
  <official_title>The Effect of Household-based Screening on Blood Pressure Changes in South Africa: a Regression Discontinuity Study</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>Till Bärnighausen</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
    <collaborator>
      <agency>Emory University</agency>
      <agency_class>Other</agency_class>
    </collaborator>
  </sponsors>
  <source>University Hospital Heidelberg</source>
  <oversight_info>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      This study will evaluate the effect of household-based screening and care encouragement for&#xD;
      blood pressure on subsequent changes in blood pressure. The study uses a quasi-experimental&#xD;
      regression discontinuity design with existing population-based secondary data from the 2008,&#xD;
      2010, 2012, 2014, and 2017 waves of the National Income Dynamics Study in South Africa.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Household-based screening and referral to care for blood pressure may improve blood pressure&#xD;
      control at the population level in many low- and middle-income countries.&#xD;
&#xD;
      This observational study will use a quasi-experimental regression discontinuity design to&#xD;
      evaluate the effect of household-based screening for blood pressure with care encouragement&#xD;
      for potentially hypertensive individuals on subsequent changes in blood pressure over time.&#xD;
&#xD;
      Individuals had their blood pressure measured in the household as part of the National Income&#xD;
      Dynamics Study data collection. If individuals had a measured blood pressure in the&#xD;
      hypertensive zone, they were told that they had elevated blood pressure, that high blood&#xD;
      pressure can lead to life threatening consequences, and that they should seek further care.&#xD;
      The study exploits the fact that individuals were given this information based on a hard&#xD;
      blood pressure cutoff. Therefore, the investigators will evaluate the causal effect of this&#xD;
      household-based intervention in the absence of randomization by comparing individuals with a&#xD;
      baseline blood pressure just above and below the cut off.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Completed</overall_status>
  <start_date type="Actual">February 2008</start_date>
  <completion_date type="Actual">December 2017</completion_date>
  <primary_completion_date type="Actual">December 2017</primary_completion_date>
  <study_type>Observational</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <observational_model>Other</observational_model>
    <time_perspective>Prospective</time_perspective>
  </study_design_info>
  <primary_outcome>
    <measure>Two-year change in systolic blood pressure</measure>
    <time_frame>Approximately two years based on the difference between survey waves in the years 2008, 2010, 2012, 2014, and 2017</time_frame>
    <description>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.</description>
  </primary_outcome>
  <primary_outcome>
    <measure>Nine-year change in systolic blood pressure</measure>
    <time_frame>Baseline in 2008 and approximately nine years later in 2017.</time_frame>
    <description>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.</description>
  </primary_outcome>
  <secondary_outcome>
    <measure>Health-seeking behavior</measure>
    <time_frame>Cross-sectionally in 2010, 2012, 2014, and 2018</time_frame>
    <description>Health-care utilization is measured at the household based on respondents' answer to the survey question: &quot;When did you last consult someone about your health?&quot;</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Blood pressure treatment</measure>
    <time_frame>Cross-sectionally in 2010, 2012, 2014, and 2018</time_frame>
    <description>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: &quot;Are you currently taking medicine for high blood pressure?&quot;</description>
  </secondary_outcome>
  <number_of_groups>2</number_of_groups>
  <enrollment type="Actual">3986</enrollment>
  <condition>Hypertension</condition>
  <condition>Blood Pressure</condition>
  <arm_group>
    <arm_group_label>Intervention group</arm_group_label>
    <description>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.</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Control group</arm_group_label>
    <description>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.</description>
  </arm_group>
  <intervention>
    <intervention_type>Other</intervention_type>
    <intervention_name>Household blood pressure screening with care encouragement</intervention_name>
    <description>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: &quot;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.&quot; Then the enumerators recommend that an individual seek medical care within 2 months.</description>
    <arm_group_label>Intervention group</arm_group_label>
  </intervention>
  <eligibility>
    <study_pop>
      <textblock>
        Individuals will be drawn from the 2008, 2010, 2012, and 2014 waves of the National Income&#xD;
        Dynamics Study (NIDS) with the 2017 wave used only for follow-up. The NIDS is a nationally&#xD;
        representative, household-based, survey of families and individuals from across South&#xD;
        Africa.&#xD;
      </textblock>
    </study_pop>
    <sampling_method>Probability Sample</sampling_method>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Age greater than or equal to 30&#xD;
&#xD;
          -  Valid blood pressure measurements&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Prior diagnosis of hypertension&#xD;
&#xD;
          -  Currently taking medication for blood pressure&#xD;
&#xD;
          -  Measured with a blood pressure above 140 mmHg systolic or 90 mmHg diastolic in a&#xD;
             previous wave of data&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>30 Years</minimum_age>
    <maximum_age>N/A</maximum_age>
  </eligibility>
  <overall_official>
    <last_name>Nikkil Sudharsanan, PhD</last_name>
    <role>Principal Investigator</role>
    <affiliation>Research group leader</affiliation>
  </overall_official>
  <verification_date>December 2018</verification_date>
  <study_first_submitted>November 30, 2018</study_first_submitted>
  <study_first_submitted_qc>November 30, 2018</study_first_submitted_qc>
  <study_first_posted type="Actual">December 3, 2018</study_first_posted>
  <last_update_submitted>December 5, 2018</last_update_submitted>
  <last_update_submitted_qc>December 5, 2018</last_update_submitted_qc>
  <last_update_posted type="Actual">December 7, 2018</last_update_posted>
  <responsible_party>
    <responsible_party_type>Sponsor-Investigator</responsible_party_type>
    <investigator_affiliation>University Hospital Heidelberg</investigator_affiliation>
    <investigator_full_name>Till Bärnighausen</investigator_full_name>
    <investigator_title>Alexander von Humboldt University Professor</investigator_title>
  </responsible_party>
  <keyword>Causal inference</keyword>
  <keyword>Regression discontinuity</keyword>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Hypertension</mesh_term>
  </condition_browse>
  <patient_data>
    <sharing_ipd>Yes</sharing_ipd>
    <ipd_description>The data are already publicly available at: http://www.nids.uct.ac.za/nids-data/data-access</ipd_description>
    <ipd_time_frame>Data are already available.</ipd_time_frame>
    <ipd_url>http://www.nids.uct.ac.za/nids-data/data-access</ipd_url>
  </patient_data>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT03762304
org study id: RDD - BP - South Africa
nct id: NCT03762304
lead sponsor: 
collaborator: 
is fda regulated drug: No
is fda regulated device: No
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.
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.
observational model: Other
time perspective: Prospective
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
description: 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.
measure: Nine-year change in systolic blood pressure
time frame: Baseline in 2008 and approximately nine years later in 2017.
description: 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.
measure: Health-seeking behavior
time frame: Cross-sectionally in 2010, 2012, 2014, and 2018
description: 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?"
measure: Blood pressure treatment
time frame: Cross-sectionally in 2010, 2012, 2014, and 2018
description: 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?"
arm group label: Intervention group
description: 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.
arm group label: Control group
description: 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.
intervention type: Other
intervention name: Household blood pressure screening with care encouragement
description: 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.
arm group label: Intervention group
study pop: 
sampling method: Probability Sample
criteria: 
gender: All
minimum age: 30 Years
maximum age: N/A
last name: Nikkil Sudharsanan, PhD
role: Principal Investigator
affiliation: Research group leader
responsible party type: Sponsor-Investigator
investigator affiliation: University Hospital Heidelberg
investigator full name: Till Bärnighausen
investigator title: Alexander von Humboldt University Professor
mesh term: Hypertension
sharing ipd: Yes
ipd description: The data are already publicly available at: http://www.nids.uct.ac.za/nids-data/data-access
ipd time frame: Data are already available.
ipd url: http://www.nids.uct.ac.za/nids-data/data-access