1. True prevalence of resistant hypertension In order to obtain the true burden of resistant hypertension, a uniform definition of resistant hypertension were applied, AHA definition[4], "high blood pressure (BP) remained in spite of appropriate lifestyle interventions and treatment of three or more different types of antihypertensive drugs at optimal dose, including at least one diuretics or achieving adequate BP control with optimal doses of 4 or more antihypertensive drugs.