Final Results of Diuretic vs Alpha-blocker Comparison Published

Linda Brookes, MSc


August 29, 2003

In This Article


The original design of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) included an alpha-blocker, doxazosin, as one of the new antihypertensive agents to be compared with the diuretic, chlorthalidone.[1] This arm of the study was halted in February 2000 after an interim analysis showed that patients treated with doxazosin had a statistically significant 25% increased risk of combined cardiovascular events, including twice the risk of developing congestive heart failure (CHF), compared with patients who received chlorthalidone.[2] This analysis showed no difference between the 2 agents with regard to the primary endpoint, fatal coronary heart disease (CHD) and nonfatal myocardial infarction (MI), or with regard to all-cause mortality. The results of this analysis, which included findings up to December 1999, were published shortly after termination of this arm of the study. Now the final data for this part of the ALLHAT study have been published in Hypertension.[3] They include an additional 9232 participant-years and 939 events up to February 15, 2000. The ALLHAT investigators say that these final results "extend and confirm the previously reported analysis of the doxazosin/chlorthalidone comparison in ALLHAT."

Of the 42,418 patients randomized in ALLHAT, 9061 received doxazosin and 15,255 received chlorthalidone. Both groups had similar characteristics at baseline, with almost equal percentages of men and women, more than one third blacks, and 16% Hispanic. Mean age was 67 years and mean blood pressure at baseline was 146/84 mm Hg. Nearly 90% of patients had received antihypertensive medication before randomization. Mean follow-up in these patients was 3.2 years.