NEW ORLEANS, LA–Angiotensin II receptor blockers (ARBs) and calcium channel blockers (CCBs) are equally effective at improving cardiovascular outcomes in patients with hypertension and glucose intolerance, according to results of the NAGOYA Heart Study, the first randomized study to compare the two drug classes presented today at ACC.11, the American College of Cardiology’s 60th Annual Scientific Session.
The study builds upon several previous nonrandomized analyses that also compared ARBs to CCBs but yielded conflicting results, thus preventing the establishment of a preferred first-line treatment for patients with hypertension and glucose intolerance. Both drug classes help to lower blood pressure (BP) by dilating blood vessels, but they do so by blocking two different chemicals, angiotensin II and calcium, respectively.
For the study, researchers enrolled 1,150 patients 30–75 years of age with hypertension who had either type 2 diabetes or impaired glucose tolerance at 46 Japanese facilities. The participants were randomized to receive a first-line treatment of either an ARB (valsartan [Diovan]; n=575) or a CCB (amlodipine [Norvasc]; n=575) between October 2004 and July 2010.
Each patient was followed for an average of 3.2 years and underwent follow-up analysis monthly for the first 3 months and then once every 1 to 3 months thereafter. During the follow-up visits, the team tested BP and HbA1c levels to study how each patient’s BP and glucose intolerance progressed. They also tracked the incidence of primary outcomes (acute heart attack, stroke, coronary revascularization, hospital admission due to congestive heart failure, and sudden cardiac death), which occurred in 54 patients (9.4%) who were taking valsartan vs. 56 patients (9.7%) who were taking amlodipine (HR=0.97 [0.66–1.4]; P=0.85), an insignificant difference.
When primary outcomes were examined individually, researchers found no significant differences between the drugs in four of the five outcomes. A significant difference was present only for hospital admission after congestive heart failure, which occurred more frequently in patients taking valsartan than in those taking amlodipine (0.5% vs. 2.6%) (HR= 0.20; [0.06-0.69]; P=0.01). There was also no significant difference in all-cause mortality or adverse events.
Researchers also found no significant difference in BP: 131/73mmHg in the valsartan group vs. 132/74mmHg in the amlodipine group at 54 months – or in HbA1c levels, which both decreased 6.7% in the same time period.
“Our study showed no difference in the efficacies between ARBs and CCBs in terms of prevention of major cardiovascular events, although the ARB was superior to the CCB regarding the prevention of heart failure,” said lead study author Toyoaki Murohara, MD, PhD from the Nagoya University Graduate School of Medicine in Nagoya, Japan. “These results highlight the safety and efficacy of ARBs, especially in preventing heart failure in diabetic hypertensive patients.”