The drugs most widely used to lower blood pressure are no more effective than old-fashioned water pills at preventing heart attack or fatal heart disease in diabetics, new U.S. and Canadian research shows.
What's more, diuretics worked better at preventing congestive heart failure in diabetics. And, in an unexpected finding, there were more heart attacks in people with "pre-diabetes" who were on a calcium channel blocker than those on a diuretic.
"It's like Aspirin. Sometimes an old drug proves to be the best treatment," said Dr. Paul Whelton, lead author of the study published in this week's Archives of Internal Medicine.
The team announced two years ago that water pills were best when first treating most people with blood pressure problems. But they took a second look at diabetics, who urgently need to control blood pressure.
Diabetics need newer drugs right away, many doctors still believe. This study says they don't.
Two million Canadians have diabetes, a number expected to increase dramatically as the population ages. The majority have type 2 diabetes, almost 75 per cent of whom have high blood pressure, intensifying their risk for heart and kidney diseases.
ACE (angiotensin converting enzyme) inhibitors are now recommended as first-line therapy for diabetics with kidney disease. But most doctors are using ACE inhibitors with all diabetics, whether or not they have kidney disease. "The majority of diabetics do not (have kidney disease)," Whelton said.
The newer pills cost up to $1.90 a day plus dispensing fees, versus under a nickel for a diuretic.
In the study, 31,512 patients 55 and older received either a diuretic (chlorthalidone), calcium channel blocker (amlodipine), or ACE inhibitor (lisinopril). Overall, 13,101 had diabetes, and nearly 1,400 had elevated fasting glucose, a symptom of pre-diabetes.
There was no evidence the newer drugs were any better than the diuretic at preventing heart disease, death, end-stage kidney disease, or cancer in those with diabetes and pre-diabetes and non-diabetics.
In both diabetics and non-diabetics, the water pills were better at protecting against heart failure by about one-third compared to calcium channel blockers, and by about one-sixth compared to ACE inhibitors. They were also better than ACE inhibitors in preventing stroke.
Dr. Frans Leenen, the lead Canadian investigator, stressed no one should change their blood pressure medicines without consulting their doctor.
© The Gazette (Montreal) 2005
