Ahmed KS, et al. - Given that the aldosterone/renin ratio is the initial screening test for primary hyperaldosteronism (PHA), researchers intended to determine ethnic variations in this retrospective study. After the clinical observation of a high prevalence of abnormal aldosterone/renin ratio (ARR) in African-origin patients, all measurements of ARR were retrospectively reviewed in a single centre over 10 years. When available, hypokalaemia, intraventricular septal thickness (IVS, by echocardiography) and adrenal imaging rates were recorded. There was an aldosterone/renin ratio in 1473 patients and an abnormal 374 patients. In 55.6% of African-origin patients screened at an Irish hospital, ARR was abnormal. Hypokalaemia rates were similar among patients of European and African origin. These findings have implications for the use of current screening guidelines for ARR in patients of African-origin as well as the mechanical role of aldosterone in African-origin patients in hypertensive complications.