ASCOT trial data show that an amlodipine-based regimen significantly reduces blood pressure and the risk for new-onset diabetes in patients with hypertension compared with a beta-blocker-based regimen, according to a presentation at the World Congress of Cardiology.

The international Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) (nearly 20,000 patients) evaluated hypertension regimens based on either a calcium channel blocker (amlodipine with or without the angiotensin-converting enzyme inhibitor perindopril) or a beta blocker (atenolol with or without the diuretic bendroflumethiazide).

Of the19,257 patients enrolled in the study, 14,120 did not have diabetes at baseline. Of this group, 1,366 patients developed diabetes over the study period: 567 (8 percent) in the amlodipine arm and 799 (11.4 percent) in the atenolol arm.

"One of the most important risk factors for developing new-onset diabetes was being allocated to the beta-blocker plus or minus diuretic treatment strategy," Dr Ajay Gupta of the International Centre for Circulatory Health, Imperial College London, UK, said. "Patients allocated to the more modern blood pressure-lowering strategy - amlodipine plus or minus perindopril - were 34 percent less likely to develop diabetes. This is important as diabetes significantly increases the risk of myocardial infarctions and strokes."

Additionally, the ASCOT study showed that patients who received the beta-blocker-based regimen were at increased risk of new-onset diabetes irrespective of all other diabetes risk factors, e.g. increased weight, blood glucose at study entry, and initial blood pressure level.

Results of the five-year ASCOT trial showed that patients on the amlodipine based regimen experienced an 11-percent reduction in total mortality, a 23-percent reduction in fatal and non-fatal strokes and a 24-percent reduction in cardiovascular death compared with patients taking the beta-blocker-based regimen. In addition, they had a 10-percent reduction in the primary endpoint of fatal coronary heart disease and non-fatal myocardial infarction, which did not reach statistical significance as the study was halted early due to the mortality benefit associated with the amlodipine-based regimen.

The early cessation of the study because of the benefits of the amlodipine plus or minus perindopril regimen in the secondary endpoint of all cause mortality meant that there was not enough statistical power for the primary endpoint (non-fatal myocardial infarction + fatal coronary heart disease) to reach statistical significance, although there was a non-significant 10 percent reduction in favor of the amlodipine strategy.

The secondary endpoint included all-cause mortality, cardiovascular mortality, fatal and non-fatal stroke, and total coronary events and procedures all of which were significantly reduced by the use of the newer regimen. New onset diabetes was a pre-specified tertiary end point.