Guidelines for antihypertensive treatment: an update after the ALLHAT study

Abstract

The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) Study, the largest double-blind, randomized trial in hypertensive patients, confirmed and strengthened the clinical relevance of thiazide diuretics in the treatment of hypertension but did not prove the superiority of these drugs. Its claim of the superiority of chlorthalidone was based on some secondary outcomes, principally represented by (1) an increased incidence of stroke in the doxazosin and lisinopril arms, an effect that might be explained by differences in systolic BP; (2) greater morbidity but not mortality for congestive heart failure (CHF) in the doxazosin, amlodipine, and lisinopril arms, a finding that might reflect poor accuracy in the diagnosis and/or especially the switching from diuretic treatment in 90% of patients. Moreover, the ALLHAT study has other limitations, and its conclusions are in contrast with data from overall controlled clinical trials indicating that given the same BP reduction, the benefit of different drug classes is similar. As to whether the ALLHAT study will influence ongoing guidelines concerning the choice of antihypertensive drugs, the answer is "yes" if interpretation of its data in favor of diuretics and cost of drugs become the preponderant considerations, as it was in recent JNC VII guidelines. However, the more liberal approach based on the choice of all available drug classes seems still to be valid, as is in the ESH-ESC guidelines, if the preponderant consideration is that the real benefit of antihypertensive therapy is due to efficient BP control and not to a particular benefit of a single drug class.