Using two simple blood tests, researchers were able to drastically improve treatment for resistant hypertension across three sites in Nigeria, Kenya and South Africa. The study demonstrates that for patients in Africa with hard-to-control hypertension, identifying the cause was the key to lowering blood pressure. By testing patients’ levels of plasma renin in combination with levels of aldosterone, physicians were able to identify the physiological changes causing the hypertension. This led to personalized and more accurate therapy.