Forty-five hypertensive CKD patients, who were already receiving antihypertensive treatment comprised of renin-angiotensin system inhibitors (angiotensin receptor blockers, ARBs; angiotensin-converting enzyme inhibitors, ACEIs; and/or direct renin inhibitor, DRI) and one of the CCBs other than cilnidipine at a standard dose for a period of more than four weeks, were enrolled from April, 2008, to November, 2011. Here, REN is linked to chronic kidney disease.