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