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NCT Number: NCT03762304

The Effect of Household-based Screening on Blood Pressure Changes in South Africa

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.

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Key information

Conditions

Hypertension Blood Pressure Cardiovascular Diseases Vascular Diseases

Age range

30 year and older

Sex eligibility

All sexes

Study type

Observational

About this study

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.

Who can participate

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age greater than or equal to 30
  • Valid blood pressure measurements

Exclusion criteria

  • 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

Treatment and study plan

Household blood pressure screening with care encouragement

Other

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.

Primary outcomes

  1. 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.

  2. 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.

Secondary outcomes

  1. Health-seeking behavior

    Time frame: Cross-sectionally in 2010, 2012, 2014, and 2018

    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?"

  2. Blood pressure treatment

    Time frame: Cross-sectionally in 2010, 2012, 2014, and 2018

    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?"

Sponsors and collaborators

Lead sponsor

Till Bärnighausen

Other

Collaborators

  • Emory University

Registry information

Official study title

The Effect of Household-based Screening on Blood Pressure Changes in South Africa: a Regression Discontinuity Study

Important dates

Study start
2008
Primary completion
2017
Study completion
2017
First posted
Dec 3, 2018
Registry last updated
Dec 7, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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