Olmesartan fails to improve renal outcome in diabetes
MedWire News: Olmesartan treatment in Type 2 diabetes patients with overt nephropathy and renal insufficiency fails to improve renal outcomes when added to antihypertensive therapy, report Japanese researchers.
The add-on angiotensin receptor blocker (ARB) reduces proteinuria and blood pressure (BP) but does not further improve renal outcomes in patients already treated with a contemporary regimen.
Led by Enyu Imai (Nagoya University, Aichi), the investigators conducted ORIENT (Olmesartan Reducing Incidence of Endstage Renal Disease in Diabetic Nephropathy Trial) to examine the renoprotective benefits of olmesartan medoxomil.
The team randomly assigned 577 Type 2 diabetes patients, already treated with antihypertensive therapy, to receive once-daily olmesartan (10-40 mg) or placebo for a mean of 3.2 years. Most patients (74%) were taking an angiotensin-converting enzyme inhibitor.
The primary composite endpoint was time to the first occurrence of doubling of serum creatinine (SCr), end-stage renal disease, or death. The safety of olmesartan and its effect on BP, renal function, proteinuria, and cardiovascular (CV) disease were also assessed.
As reported in the journal Diabetologia, the primary endpoint was met by 116 individuals in the olmesartan group and by 129 in the placebo group, at a nonsignificant hazard ratio of 0.97.
Olmesartan was associated with significant reductions in blood pressure, proteinuria, and rate of change in reciprocal serum creatinine.
However, subgroup analysis revealed that the majority of the renal endpoints occurred in patients with accelerated decline in renal function rather than in the group as a whole.
"This suggests that treatment with olmesartan did not confer additional renoprotection, especially in patients with rapidly declining renal function," write Imai and team.
The authors also found that olmesartan-treated patients had numerically fewer major adverse cardiac events (CV death plus non-fatal stroke and myocardial infarction) than the placebo group (18 vs 21 cases).
However, they say the study did not have sufficient power to determine the effects of olmesartan on CV outcomes.
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By Sally Robertson