Patients given a mix of modern blood pressure drugs are one-third less likely to develop diabetes than those on older pills, researchers said on Wednesday.

A new analysis of Europe’s biggest-ever study of hypertensive patients showed 8 percent given newer medicines developed diabetes after five years, against 11.4 percent of those on older drugs.

The 19,000-person trial was halted back in November 2004 because the newer drugs proved so much better in reducing strokes and heart attacks.

It compared a regimen of a beta-blocker and a diuretic with a combination of Pfizer Inc.‘s Norvasc and Coversyl, which was developed by France’s Servier and is marketed in the United States as Aceon by Solvay SA and CV Therapeutics Inc.

Norvasc, known generically as amlodipine, is a calcium channel blocker, while Coversyl, or perindopril, is an ACE inhibitor.

The clinical trial was paid for by Pfizer.

Professor Peter Sever of Imperial College in London, co-chairman of the study, said the findings underlined the limitations of beta-blockers for treating high blood pressure.

Britain’s National Institute for Health and Clinical Excellence (NICE) cost-effectiveness watchdog recently said beta-blockers should no longer be the preferred initial therapy, and Sever said other authorities were likely to follow suit.

He believes the reason for the difference between treatment with beta-blockers and newer drugs is largely down to the way in which beta-blockers restrict blood flow to muscles, making it more difficult for the body to metabolize glucose.

“In my view, the major culprit is the beta-blocker,” he told Reuters, adding that calcium channel blockers and ACE inhibitors probably also helped positively by dilating blood vessels.