Effects of up-titration of candesartan versus candesartan plus amlodipine on kidney function in type 2 diabetic patients with albuminuria

In the present study, we tested the hypothesis that up-titrating the dose of an angiotensin receptor blocker (ARB) is superior to combined treatment with an ARB and a calcium channel blocker for the same degree of blood pressure (BP) reduction, with respect to urinary albumin excretion in diabetic patients treated with a standard dose of the ARB. Hypertensive patients with type 2 diabetes mellitus and albuminuria (≥30?mg?g(-1) creatinine) were enroled in the study, and were either started on or switched to candesartan (8?mg per day) monotherapy. After a 12-week run-in period, baseline evaluations were performed and patients with BP ≥130/80?mm?Hg were randomly assigned to receive either candesartan (12?mg per day) or candesartan (8?mg per day) plus amlodipine (2.5?mg per day) for a further 12 weeks. The primary end-point was a reduction in urinary albumin levels. Although there was no significant difference in the BP reduction between the two groups, the reduction in urinary albumin was greater in the up-titrated than the combination therapy group (-40±14% vs -9±38%, respectively; P<0.0001). Thus, up-titration of candesartan more effectively reduces urinary albumin excretion than combined candesartan plus amlodipine in hypertensive patients with diabetes for the same degree of BP reduction.