Diuretics (water pills) work better than newer and more costly medicines in the treatment of high blood pressure and prevention of some forms of heart disease in people with type 2 diabetes, according to results from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).
ALLHAT, the largest hypertension clinical trial ever conducted, was led in part by Tulane University physician and epidemiologist Paul K. Whelton, senior vice president for health sciences and lead author for the current report published in the June 27th issue of the Archives of Internal Medicine.
"Almost three out of every four persons with type 2 diabetes has hypertension, putting them at substantial risk for cardiovascular disease," Whelton says.
An important question in patients with type 2 diabetes and hypertension has been whether it makes a difference which medicine is used for initial therapy of high blood pressure.
"ALLHAT is the largest study to address this question, comparing four different classes of antihypertensive medication: diuretics, angiotensin-converting enzyme [ACE] inhibitors, calcium channel blockers and alpha receptor blockers," Whelton says.
In an earlier publication (Journal of the American Medical Association, December 2002), the ALLHAT investigators reported that diuretics were superior in preventing adverse cardiovascular disease outcomes compared with other first-step antihypertensive medications. The current report indicates that this is true not only in hypertensive patients with a normal blood sugar, but in those with diabetes, or an impaired fasting glucose (pre-diabetes).
The Archives publication was based on long-term clinical trial experience in 31,512 men and women who were all 55 years old or older with stage 1 or stage 2 hypertension and at least one additional risk factor for coronary heart disease. Study participants were assigned to initial treatment with either a calcium channel blocker (amlodipine), an ACE inhibitor (lisinopril) or a diuretic (chlorthalidone). Compared with the ACE inhibitor and the calcium channel blocker, the diuretic was:
- More protective against heart failure in patients with or without diabetes (by about 1/6th compared with the ACE inhibitor, and by about 1/3rd compared with the calcium channel blocker).
- More protective against stroke in people with or without diabetes (compared with the ACE inhibitor). This benefit was seen only in Black patients.
- Slightly more effective in lowering systolic blood pressure-the measure of blood pressure when the heart beats-among those with or without diabetes.
- At least equally protective against fatal coronary heart disease or non-fatal heart attacks in diabetics, those with an impaired fasting glucose, and in those with a normal blood sugar.
- Equally protective against death, end-stage renal disease or cancer in diabetics, those with an impaired fasting glucose, and in those with a normal blood sugar.
"Independent of diabetes status, our results suggest that diuretics are better than ACE inhibitors and calcium channel blockers in preventing certain cardiovascular disease complications-especially heart failure-during initial treatment of high blood pressure. Patients with diabetes and high blood pressure should not change their antihypertensive medications without discussing this option with their doctors," says Whelton.