Among elderly hypertensive patients in Japan, adding a calcium channel blocker (CCB) to an angiotensin II receptor blocker (ARB) provided better blood pressure control than a doubled dose of the ARB.
Dr. Shokei Kim-Mitsuyama from Kumamoto University Graduate School of Medical Sciences told Reuters Health by email, "We think that ARB plus CCB combination therapy is suitable for antihypertensive treatment in elderly hypertensive patients with previous cardiovascular disease" -- whereas for some diabetics, high dose ARBs will be enough to control hypertension.
Dr. Kim-Mitsuyama and colleagues in the OSCAR study group randomly assigned 1,164 elderly Japanese patients with cardiovascular disease or type 2 diabetes to receive either olmesartan 40 mg or olmesartan 20 mg plus amlodipine or azelnidipine.
At 36 months, mean systolic and diastolic blood pressures were lower by 2.4 mm Hg (p=0.03) and 1.7 mm Hg (p=0.02), respectively, in the combination therapy group, the research team reported online April 14 in The American Journal of Medicine.
Also, significantly more patients in combination group achieved the target blood pressure of <140/90 mm Hg (p=0.003).
There were fewer primary end points in the ARB plus CCB group than in the high-dose ARB group, but the difference failed to achieve statistical significance overall.
However, in the prespecified subgroup analysis of patients with cardiovascular disease, the incidence of primary end points (fatal and non-fatal cardiovascular events and non-cardiovascular deaths) was 63% higher in the high-dose ARB group than in the ARB plus CCB group (p=0.03).
Therefore, the researchers note, the effect of treatment "might differ depending on whether patients have cardiovascular disease; this finding is not definitive but may be considered as hypothesis generating."
The number of serious adverse events did not differ between the two treatment groups, according to their report.
"We have ongoing several kinds of subgroup analysis according to eGFR, sex, age, etc.," Dr. Kim-Mitsuyama said. "We hope that further subanalysis will provide new insight into ARB-based antihypertensive therapy."
Am J Med 2012.