Patients with hypertension who take calcium-channel blockers and diuretics have an increased risk for death due to cardiovascular disease death compared with patients who take beta-blockers plus diuretics, according to a study in the December 15th issue of the Journal of the American Medical Association. Other findings indicate that diuretics may be the preferred single medication to preventing cardiovascular complications.

Although previous research has indicated that diuretics are equal or superior to other antihypertension medications as initial monotherapy, most patients with hypertension require more than one drug class to control blood pressure. It has been unresolved which other drug classes added to diuretics have fewer effects on cardiovascular complications.

Sylvia Wassertheil-Smoller, PhD, and her American colleagues examined the relation of different classes of antihypertensive drugs to the incidence of coronary heart disease, stroke, and death due to cardiovascular disease. The researchers analyzed data for women with hypertension enrolled in the Women’s Health Initiative Observational Study, a multicenter study of 93,676 women aged 50 to 79 years at baseline (1994-1998), assessed for an average of 5.9 years.

Among 30,219 women with hypertension but no history of cardiovascular disease, 19,889 were on pharmacological antihypertensive treatment, of whom 11,294 (57 percent) were receiving monotherapy with an angiotensin-converting enzyme (ACE) inhibitor, beta-blocker, calcium-channel blocker, or diuretic, and 4,493 (23 percent) were treated at baseline with a combination of diuretic plus either ACE inhibitor, beta-blocker, or calcium channel blocker or ACE inhibitor plus calcium-channel blocker.

The researchers found that among two-drug-class combinations, diuretics plus calcium-channel blockers were associated with approximately double the risk of cardiovascular death compared with diuretics plus beta-blockers. For events related to coronary heart disease or stroke, diuretics plus ACE inhibitors or calcium-channel blockers did not differ from diuretics plus beta-blockers. Monotherapy with calcium-channel blockers vs. diuretics was associated with a 55 percent increased risk of cardiovascular death.

“The findings of this observational study concerning monotherapy are consistent with the comparative clinical trials published thus far and support the current guidelines set forth in the report of the JNC 7 [Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure], which recommend low-dose diuretic therapy for most patients with hypertension,” the authors wrote.