Almost one in three American adults has high blood pressure (also known as hypertension ). However, about 30% of people with hypertension don’t even know they have it. Hypertension is sometimes called the “silent killer,” as it often occurs without symptoms but can create very real damage in the body, affecting the heart, kidney, and brain.

High blood pressure is the number one risk factor for congestive heart failure (CHF) and a major risk factor for heart attack . It has also been associated with stroke —very high blood pressure can cause a weakened blood vessel to break and bleed into the brain. In addition, high blood pressure can narrow and thicken the small blood vessels of the kidney leading to kidney damage and end-stage renal disease (ESRD).

High blood pressure occurs more often among African Americans than whites. It begins at an earlier age, and its effects are more frequent and severe. Additionally, African Americans have a higher death rate from stroke and kidney disease—both complications of hypertension—than whites.

Many types of medications are available to treat high blood pressure, and most are effective to some degree. Research is ongoing to see how these different drug classes compare in lowering blood pressure and decreasing risk for additional damage to the heart, brain, and kidneys in both African Americans and whites. A study published in the April 6, 2005 issue of the Journal of the American Medical Association looked at how a relatively low cost thiazide-type diuretic compared to pricier drug treatments for lowering blood pressure and reducing cardiovascular risk in black and non-black patients.

About the Study

The study was based on data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). ALLHAT enrolled more than 40,000 participants and looked at several different medication classes—thiazide-type diuretics, alpha-blockers, angiotensin-converting enzyme inhibitors (ACE inhibitors), and calcium channel blockers (CCBs)—and their ability to lower blood pressure and prevent adverse outcomes such as coronary heart disease (CHD), CHF, stroke, and ESRD.

The authors of this study analyzed the ALLHAT data by race and focused on whether an ACE inhibitor or a CCB was superior to a thiazide-type diuretic in reducing cardiovascular disease (CVD) incidence in racial subgroups. The study included more than 33,000 ALLHAT participants who had high blood pressure, were 55 or older, and had at least one other cardiovascular risk factor (e.g., type 2 diabetes, current cigarette smoking, or previous heart attack or stroke).

The ALLHAT participants were randomized to begin hypertensive treatment with an ACE inhibitor, CCB, or thiazide-type diuretic. Goal blood pressure for all patients was less than 140/90 mm Hg—the threshold measure above which blood pressure is considered high. Additional medications could be used if participants were not reaching the goal. Blood pressure was checked every three months during the first year and every four months for the duration of the study. Average follow-up was 4.9 years.

The Findings

Although both blacks and non-blacks achieved blood pressure reductions in the trial, non-black patients achieved greater blood pressure reductions across all treatment groups (see the following table).

Medication type% Black participants who achieved a BP of < 140/90% Non-black participants who achieved a BP of < 140/90
Thiazide-type diuretic63%69%

Rates for nonfatal heart attack and fatal CHD were significantly lower in black than non-black patients. But, black patients had significantly higher rates of stroke and end-stage renal disease.

When researchers looked at how CCBs and ACEIs compared to thiazide-type diuretics in both racial subgroups, neither were superior to the less expensive diuretic in preventing CHD or any other clinical outcome. For both black and non-black patients, risk of CHF and CVD was significantly lower with the diuretic than the ACE inhibitor. Additionally, the risk of stroke was lower with the diuretic than the ACE inhibitor for black patients.

How Does This Affect You?

According to the most recent guidelines, almost two-thirds of people with hypertension are not adequately treated. Additionally, most people require more than one drug to get their blood pressure under control. Because of the dire consequences of hypertension, control is critically important.

Fortunately, there are many medications available to a patient with hypertension—from the older, generic, less expensive diuretics to newer, brand name, more expensive drugs like ACEIs and CCBs. With the cost of drug therapy high and climbing, it is pleasantly surprising to learn more money does not buy better results. A diuretic is just as effective—in fact, sometimes more effective—when compared to the newer, more costly blood-pressure lowering drugs. And this holds true for both black and non-black patients.

If your high blood pressure is being successfully treated with an ACE inhibitor, CCB or other non-diuretic, there is probably no reason to switch. However, if your blood pressure is not adequately controlled or you are having intolerable side effects with your current non-diuretic medication, a thiazide diuretic may be indicated. Either way, it is essential that you follow-up with your doctor regularly to keep your blood pressure under control.