Most patients will need a treatment cocktail—including a thiazide diuretic

Hypertension is one of the most important preventable causes of premature death worldwide,1 and the benefits of antihypertensive drugs have been confirmed by the largest evidence base from clinical trials in medicine. Many classes of drugs are available for treatment, and debate has raged about whether the benefits of treatment are purely a function of the quality of blood pressure control or whether the type of drug used might also be a powerful determinant of outcome. This is a key question because the difference in cost between “older” drugs (thiazides or β blockers) and “newer” drugs (such as angiotensin converting enzyme (ACE) inhibitors or calcium channel blockers) is substantial. A meta-analysis of trials of treatment for hypertension with the newer drugs found that ACE inhibitors and calcium channel blockers were likely to reduce cardiovascular morbidity and mortality by the same order of magnitude as β blockers or thiazides,2 but such analyses have insufficient statistical power to detect cause specific outcomes with regard to specific drugs.

Recently, the “antihypertensive and lipid lowering to prevent heart attack trial” (ALLHAT)—the largest ever randomised trial of antihypertensive treatment—reported its results.3 It was designed to determine whether the choice of first line treatment for hypertension influenced cardiovascular outcome. Importantly, the trial was sufficiently large to examine cause specific outcomes and was the first hypertension study to have sufficient power to examine the combined incidence of fatal coronary heart disease and non-fatal myocardial infarction as the primary end point.

ALLHAT was a randomised double blind controlled clinical trial conducted in 623 centres in North America. …