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

Till Bärnighausen

Status: Completed

Conditions: Hypertension; Blood Pressure

Treatments: Other: Household blood pressure screening with care encouragement

Study type: Observational

Funder types: Other

Identifiers

NCT03762304

RDD - BP - South Africa

Details and patient eligibility

About

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.

Full 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.

Enrollment: 3,986 patients

Sex: All

Ages: 30+ years old

Volunteers: No Healthy Volunteers

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

Trial design

3,986 participants in 2 patient groups

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.

Treatment:

Other: Household blood pressure screening with care encouragement

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.