Olmesartan for the Delay or Prevention of Microalbuminuria in Type 2 Diabetes
What is the effect of treatment with olmesartan on the occurrence of microalbuminuria in patients with type 2 diabetes and normoalbuminuria?
The investigators randomly assigned 4,447 patients with type 2 diabetes to receive olmesartan (at a dose of 40 mg once daily) or placebo for a median of 3.2 years. Additional antihypertensive drugs (except angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers [ARBs]) were used as needed to lower blood pressure to <130/80 mm Hg. The primary outcome was the time to the first onset of microalbuminuria. The times to the onset of renal and cardiovascular events were analyzed as secondary endpoints.
The target blood pressure (<130/80 mm Hg) was achieved in nearly 80% of the patients taking olmesartan and 71% taking placebo; blood pressure measured in the clinic was lower by 3.1/1.9 mm Hg in the olmesartan group than in the placebo group. Microalbuminuria developed in 8.2% of the patients in the olmesartan group (178 of 2,160 patients who could be evaluated) and 9.8% in the placebo group (210 of 2,139); the time to the onset of microalbuminuria was increased by 23% with olmesartan (hazard ratio for onset of microalbuminuria, 0.77; 95% confidence interval, 0.63-0.94; p = 0.01). The serum creatinine level doubled in 1% of the patients in each group. Slightly fewer patients in the olmesartan group than in the placebo group had nonfatal cardiovascular events—81 of 2,232 patients (3.6%) compared with 91 of 2,215 patients (4.1%) (p = 0.37), but a greater number had fatal cardiovascular events—15 patients (0.7%) compared with 3 patients (0.1%) (p = 0.01), a difference that was attributable in part to a higher rate of death from cardiovascular causes in the olmesartan group than in the placebo group among patients with pre-existing coronary heart disease (11 of 564 patients [2.0%] vs. 1 of 540 [0.2%], p = 0.02).
The authors concluded that olmesartan was associated with a delayed onset of microalbuminuria.
The primary finding of this study is that ARB-based therapy with olmesartan in patients with type 2 diabetes increased the time to the onset of microalbuminuria by 23%. The overall rates of cardiovascular and cerebrovascular events in the present study were low, but there were more deaths from cardiovascular causes in the olmesartan group than in the placebo group. An excessive reduction of blood pressure in some high-risk patients may have conferred a predisposition to an increased risk of death, a finding that is consistent with the well-known, somewhat controversial ‘J-curve effect’; however, a direct effect of olmesartan cannot be ruled out and requires additional evaluation.
Keywords: Imidazoles, Diabetes Mellitus, Type 2, Blood Pressure, Tetrazoles
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