Similar Clinical Outcomes With ARB, CCB for HTN in Diabetics

April 08, 2011

April 8, 2011 (New Orleans, Louisiana) — Although guidelines tend to prefer ACE inhibitors or ARBs as the basis for hypertension drug therapy in diabetics, in whom they can protect against nephropathy, the jury is still out on whether CCBs might lead to better clinical outcomes, according to Dr Toyoaki Murohara (Nagoya University School of Medicine, Japan).

In the NAGOYA-HEART Study, whose primary findings Murohara reported here at the American College of Cardiology (ACC) 2011 Scientific Sessions/i2 Summit, there was no difference between the two antihypertensive strategies in patients with type 2 diabetes or impaired glucose tolerance with respect to a primary composite end point consisting of acute MI, stroke, coronary revascularization, heart-failure hospitalization, or sudden cardiac death over three years or in the secondary end point of all-cause mortality.

Although the end point wasn't prespecified, heart-failure hospitalizations were significantly fewer among those getting ARB-based therapy.

To heartwire , Murohara said the findings support current guidelines in indicating a preference for ARBs in hypertensive diabetics, largely because they, but not CCBs, have been shown to curtail progression to heart failure--as was suggested in the NAGOYA HEART Study.

The trial equally randomized 1150 patients with hypertension--82% of whom also had type 2 diabetes and 18% of whom had impaired glucose tolerance--at 46 centers in Japan to blood-pressure-lowering therapy based on either the ARB valsartan (Diovan, Novartis) or the CCB amlodipine (Norvasc, Pfizer).

The open-label therapy was aimed at a blood-pressure goal of <130/80 mm Hg; clinical outcomes were adjudicated in blinded fashion.

The treatment groups were similar at baseline with respect to age (mean 63 years); body-mass index; medications; standard CV risk factors; and lipid and renal biomarkers. Men made up two-thirds of the population. Excluded were patients with renal dysfunction or an LVEF <40 and those with a CV-disease event within the past six months; 69% had no history of coronary disease or stroke.

Blood-pressure and glycated hemoglobin levels were "equally controlled" over the follow-up averaging 3.2 years, according to Murohara. The composite primary end point occurred in 9.4% of patients on valsartan and 9.7% of those on amlodipine, for an ARB-vs-CCB hazard ratio (HR) of 0.97 (95% CI 0.66–1.40; p=0.85). All-cause mortality was 3.8% and 2.8%, respectively, also not a significant difference. The analysis was controlled for age, sex, statin use, smoking status, and whether the patient had diabetes or impaired glucose tolerance.

The rate of HF hospitalization, the only component of the primary end point to show a significant difference, was 0.5% for valsartan and 2.6% for amlodipine (p=0.012).

There weren't enough patients to show any differential subgroup effects of the two regimens, Murohara said. Therefore, it couldn't be shown whether valsartan might have prevented patients with impaired glucose tolerance from progressing to overt diabetes. As previously reported by heartwire , such a protective effect was suggested for ARBs in the NAVIGATOR trial but not for ACE inhibitors in the DREAM trial, although neither were hypertension trials.

The study was funded by Nagoya University Graduate School of Medicine. Murohara discloses receiving fees for speaking from Daiichi-Sankyo, Novartis, Pfizer, and Takeda.


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