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

Hypertension Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03762304
• Other study ID #: RDD - BP - South Africa
• Status: Completed
• Start date: February 2008
• Est. completion date: December 2017

Study information

• Verified date: December 2018
• Source: University Hospital Heidelberg
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical 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 National Income Dynamics Study in South Africa.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 3986
• Est. completion date: December 2017
• Est. primary completion date: December 2017
• Gender: All
• Age group: 30 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Blood Pressure
• Hypertension

Intervention

Other:
• Household blood pressure screening with care encouragement
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.

Locations

Country	Name	City	State
n/a

Sponsors (2)

Lead Sponsor	Collaborator
Till Bärnighausen	Emory University

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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.	Approximately two years based on the difference between survey waves in the years 2008, 2010, 2012, 2014, and 2017
Primary	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.	Baseline in 2008 and approximately nine years later in 2017.
Secondary	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?"	Cross-sectionally in 2010, 2012, 2014, and 2018
Secondary	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?"	Cross-sectionally in 2010, 2012, 2014, and 2018