Two ARB-Based Regimens Found Equivalent in OSCAR

NEW ORLEANS – Treatment with high doses of an angiotensin II receptor blocker or combined treatment with an ARB and a calcium channel blocker provided equal protection against cardiovascular events in elderly hypertensive patients, in a Japanese study presented at the meeting.

There were some differences, however. Greater blood pressure lowering was achieved with the combination, though in diabetic patients cardiovascular outcomes were more likely to be improved with high-dose ARBs, reported Dr. Hisao Ogawa of Kumamoto (Japan) University.

The OSCAR (Olmesartan and Calcium Antagonists Randomized) study enrolled 1,164 high-risk elderly hypertensive patients at 134 centers throughout Japan from 2005 to 2007. Patients had hypertension uncontrolled on standard-dose monotherapy with the ARB olmesartan and had at least one of the following cardiovascular conditions: type 2 diabetes, cardiac disease, vascular disease, renal dysfunction, or cerebrovascular disease.

Patients were randomized to receive either high-dose olmesartan 40 mg/day (n = 578) or a calcium channel blocker (CCB) combined with olmesartan 20 mg/day (n = 586). The primary end point was a composite of fatal and nonfatal cardiovascular events, including coronary artery disease, heart failure, cerebrovascular disease, other arteriosclerotic disease, diabetic complications, and the deterioration of renal function as well as noncardiovascular death.

At 36 months' follow-up, in the intention-to-treat analysis, blood pressure was adequately controlled by both treatment approaches, but the combination reduced blood pressure to significantly lower levels, compared with the ARB. With combination ARB/CCB, mean systolic levels were lower by 2.4 mm Hg, and mean diastolic levels were lower by 1.7 mm Hg, both significant differences.

However, no significant differences were seen between the arms in the composite end point, with 58 events occurring with high-dose ARB treatment and 48 occurring with the combination ARB/CCB. While risk was increased by 31% with the high-dose ARB, the difference was not statistically significant, Dr. Ogawa reported.

Subgroup analyses did reveal differences between the treatments. For patients with preexisting cardiovascular disease, those randomized to the combination therapy had significantly fewer cardiovascular events or deaths than those in the monotherapy group: 34% and 51%, respectively, for a 63% increased risk, he said.

Conversely, in the subgroups of patients with only diabetes and no other evidence of cardiovascular disease, the combination therapy group was at greater risk. Events occurred in 14 patients compared with 7 patients, for a 48% reduced risk with high-dose ARBs, though this was not statistically significant.

“There was a significant treatment-by-subgroup interaction for the primary end points between the patients with and those without cardiovascular disease [only diabetes],” he said. “The OSCAR study suggests that the relative effect of the two therapies depends on the presence of cardiovascular disease or type 2 diabetes.”

The study was funded by the Japan Heart Foundation. Dr. Ogawa has received grant support from Astellas, AstraZeneca, Bayer, Boehringer Ingelheim, Daiichi Sankyo, Eisai, Kowa, Kyowa Hakko Kirin, Merck, Novartis, Pfizer, Sanofi-Aventis, Schering-Plough, and Takeda.

NEW ORLEANS – Treatment with high doses of an angiotensin II receptor blocker or combined treatment with an ARB and a calcium channel blocker provided equal protection against cardiovascular events in elderly hypertensive patients, in a Japanese study presented at the meeting.

There were some differences, however. Greater blood pressure lowering was achieved with the combination, though in diabetic patients cardiovascular outcomes were more likely to be improved with high-dose ARBs, reported Dr. Hisao Ogawa of Kumamoto (Japan) University.

The OSCAR (Olmesartan and Calcium Antagonists Randomized) study enrolled 1,164 high-risk elderly hypertensive patients at 134 centers throughout Japan from 2005 to 2007. Patients had hypertension uncontrolled on standard-dose monotherapy with the ARB olmesartan and had at least one of the following cardiovascular conditions: type 2 diabetes, cardiac disease, vascular disease, renal dysfunction, or cerebrovascular disease.

Patients were randomized to receive either high-dose olmesartan 40 mg/day (n = 578) or a calcium channel blocker (CCB) combined with olmesartan 20 mg/day (n = 586). The primary end point was a composite of fatal and nonfatal cardiovascular events, including coronary artery disease, heart failure, cerebrovascular disease, other arteriosclerotic disease, diabetic complications, and the deterioration of renal function as well as noncardiovascular death.

At 36 months' follow-up, in the intention-to-treat analysis, blood pressure was adequately controlled by both treatment approaches, but the combination reduced blood pressure to significantly lower levels, compared with the ARB. With combination ARB/CCB, mean systolic levels were lower by 2.4 mm Hg, and mean diastolic levels were lower by 1.7 mm Hg, both significant differences.

However, no significant differences were seen between the arms in the composite end point, with 58 events occurring with high-dose ARB treatment and 48 occurring with the combination ARB/CCB. While risk was increased by 31% with the high-dose ARB, the difference was not statistically significant, Dr. Ogawa reported.

Subgroup analyses did reveal differences between the treatments. For patients with preexisting cardiovascular disease, those randomized to the combination therapy had significantly fewer cardiovascular events or deaths than those in the monotherapy group: 34% and 51%, respectively, for a 63% increased risk, he said.

Conversely, in the subgroups of patients with only diabetes and no other evidence of cardiovascular disease, the combination therapy group was at greater risk. Events occurred in 14 patients compared with 7 patients, for a 48% reduced risk with high-dose ARBs, though this was not statistically significant.

“There was a significant treatment-by-subgroup interaction for the primary end points between the patients with and those without cardiovascular disease [only diabetes],” he said. “The OSCAR study suggests that the relative effect of the two therapies depends on the presence of cardiovascular disease or type 2 diabetes.”

The study was funded by the Japan Heart Foundation. Dr. Ogawa has received grant support from Astellas, AstraZeneca, Bayer, Boehringer Ingelheim, Daiichi Sankyo, Eisai, Kowa, Kyowa Hakko Kirin, Merck, Novartis, Pfizer, Sanofi-Aventis, Schering-Plough, and Takeda.

NEW ORLEANS – Treatment with high doses of an angiotensin II receptor blocker or combined treatment with an ARB and a calcium channel blocker provided equal protection against cardiovascular events in elderly hypertensive patients, in a Japanese study presented at the meeting.

There were some differences, however. Greater blood pressure lowering was achieved with the combination, though in diabetic patients cardiovascular outcomes were more likely to be improved with high-dose ARBs, reported Dr. Hisao Ogawa of Kumamoto (Japan) University.

The OSCAR (Olmesartan and Calcium Antagonists Randomized) study enrolled 1,164 high-risk elderly hypertensive patients at 134 centers throughout Japan from 2005 to 2007. Patients had hypertension uncontrolled on standard-dose monotherapy with the ARB olmesartan and had at least one of the following cardiovascular conditions: type 2 diabetes, cardiac disease, vascular disease, renal dysfunction, or cerebrovascular disease.

Patients were randomized to receive either high-dose olmesartan 40 mg/day (n = 578) or a calcium channel blocker (CCB) combined with olmesartan 20 mg/day (n = 586). The primary end point was a composite of fatal and nonfatal cardiovascular events, including coronary artery disease, heart failure, cerebrovascular disease, other arteriosclerotic disease, diabetic complications, and the deterioration of renal function as well as noncardiovascular death.

At 36 months' follow-up, in the intention-to-treat analysis, blood pressure was adequately controlled by both treatment approaches, but the combination reduced blood pressure to significantly lower levels, compared with the ARB. With combination ARB/CCB, mean systolic levels were lower by 2.4 mm Hg, and mean diastolic levels were lower by 1.7 mm Hg, both significant differences.

However, no significant differences were seen between the arms in the composite end point, with 58 events occurring with high-dose ARB treatment and 48 occurring with the combination ARB/CCB. While risk was increased by 31% with the high-dose ARB, the difference was not statistically significant, Dr. Ogawa reported.

Subgroup analyses did reveal differences between the treatments. For patients with preexisting cardiovascular disease, those randomized to the combination therapy had significantly fewer cardiovascular events or deaths than those in the monotherapy group: 34% and 51%, respectively, for a 63% increased risk, he said.

Conversely, in the subgroups of patients with only diabetes and no other evidence of cardiovascular disease, the combination therapy group was at greater risk. Events occurred in 14 patients compared with 7 patients, for a 48% reduced risk with high-dose ARBs, though this was not statistically significant.

“There was a significant treatment-by-subgroup interaction for the primary end points between the patients with and those without cardiovascular disease [only diabetes],” he said. “The OSCAR study suggests that the relative effect of the two therapies depends on the presence of cardiovascular disease or type 2 diabetes.”

The study was funded by the Japan Heart Foundation. Dr. Ogawa has received grant support from Astellas, AstraZeneca, Bayer, Boehringer Ingelheim, Daiichi Sankyo, Eisai, Kowa, Kyowa Hakko Kirin, Merck, Novartis, Pfizer, Sanofi-Aventis, Schering-Plough, and Takeda.