REN and chronic kidney disease: Hypertension is also a leading cause of chronic kidney disease (CKD) through its harmful effects on kidney vasculature; in turn, worsening CKD leads to increased sympathetic tone and salt sensitivity, upregulation of the renin–angiotensin–aldosterone system (RAAS), endothelial dysfunction, and worsening arterial stiffness, eventually driving the further progression of hypertension [4].