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

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.

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.

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