Background: A thiazide diuretic used in combination with benazepril is superior to amlodipine plus benazepril in reducing albuminuria in hypertensive patients with diabetes. However, calcium channel blockers have diverse characteristics. Thus, we investigated whether combining an angiotensin receptor blocker with either azelnidipine or a thiazide diuretic produced similar reductions in albuminuria in hypertensive diabetic patients for the same levels of blood pressure achieved.
Methods: Hypertensive patients with type 2 diabetes and albuminuria (30-600 mg/g creatinine) under antihypertensive treatment (mean age 67.0±7.6 years) were instructed to stop all antihypertensive treatment and take a combination of olmesartan (20 mg/day) and amlodipine (5 mg/day) for 3 months (run-in period). Then, patients were randomly assigned to receive either olmesartan plus azelnidipine (16 mg/day; n=71) or olmesartan plus trichlormethiazide (1 mg/day; n=72) for an additional 6 months. The primary end point was urinary excretion of albumin at 6 months after randomization.
Results: At the time of randomization, urinary albumin was 116.0 and 107.8 mg/g creatinine (geometric mean) in the azelnidipine and diuretic arms, respectively, and was reduced to a similar extent [79.8 (95% confidence interval 66.4-96.0) and 89.7 (74.6-107.7) mg/g creatinine, respectively, after adjustment for baseline values]. Blood pressure did not differ between the two groups throughout the study period.
Conclusions: Azelnidipine is equally effective as a thiazide diuretic in reducing urinary albumin when used in combination with olmesartan.
Keywords: angiotensin receptor blocker; calcium channel blocker; combination therapy; glomerular filtration rate.