In people with diabetes, diuretics work as well as angiotensin converting enzyme inhibitors and calcium channel blockers in protecting against myocardial infarction and improving survival. Furthermore, they offer more protection against congestive heart failure, according to an article in the June 27th issue of Archives of Internal Medicine.

The article represents the latest findings from the "Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial" or ALLHAT. ALLHAT is the largest study to compare the three major classes of antihypertensive medication.

The study originally reported in 2002 that diuretics were more beneficial as initial treatment for protection against adverse cardiovascular outcomes in people with hypertension. This latest analysis shows that even among diabetics and those with mildly elevated fasting glucose, diuretics are at least as effective and may be more beneficial for some people.

About 73 percent of adults with diabetes have hypertension ? which in diabetic patients is defined as greater than or equal to 130/80 mm Hg -- or use medications for hypertension. Both diabetes and hypertension are major risk factors for coronary heart disease, and when both are present, significantly increase the risk for heart and kidney disease.

"Controlling high blood pressure is an urgent concern especially for people
with diabetes. Our findings demonstrate the advantages of diuretics in
diabetics as well as in those with impaired and normal fasting glucose
levels," said NHLBI director Dr. Elizabeth G. Nabel. "As a physician, I have
seen the consequences of poorly controlled hypertension and diabetes. These
results show many people and their families can be spared that devastation."

The ALLHAT blood pressure study was a randomized, double-blind trial
involving 42,418 participants with hypertension ages 55 and older. Of those, 31,512 participants were randomly assigned to a diuretic (chlorthalidone), a calcium channel blocker (amlodipine), or an angiotensin converting enzyme (ACE) inhibitor (lisinopril). A total of 13,101 participants had diabetes, 1,399 had elevated fasting glucose levels, and 17,012 had normal glucose levels.

Compared with the ACE inhibitor and calcium channel blocker, the diuretic was more protective against congestive heart failure in all patients (by about 1/6 compared with the ACE inhibitor, and by about 1/3 compared with the calcium channel blocker).

In addition, the diuretic was more effective in lowering systolic blood pressure in people with and without diabetes and it was at least equally protective against fatal coronary heart disease or non-fatal myocardial infarctions in people with diabetes, those with elevated fasting glucose, and non-diabetics.

The diuretic was equally protective against death from all causes, end-stage kidney
disease, or cancer in people with diabetes, those with elevated fasting glucose, and non-diabetics.

"This study shows the advantage of diuretics for preventing congestive heart
failure in most people with high blood pressure -- regardless of diabetes
status. Because some patients may respond differently to medications, they
should discuss these results and their treatment with their doctors before
making any changes", advised Dr. Jeffrey Cutler, National Institutes of Health.

There were more myocardial infarctions among participants with impaired fasting
glucose taking the calcium channel blocker compared with those taking the
diuretic. This finding was unexpected and inconsistent with other results
and may have occurred just by chance, according to Cutler.

Previous studies have found that ACE inhibitors slow progression of kidney
damage in diabetic patients with kidney disease, who generally have protein
in their urine. ALLHAT did not collect urine samples to measure protein
levels so analyses o whether the ACE inhibitor was superior to the diuretic in this respect was not possible.