Putting ALLHAT into Perspective

6 Jun

Putting ALLHATPredictably, and with good reason, the outcomes of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (the ALLHAT study), reported in late 2002, drew the interest of media journalists as well as the attention of the medical community and the health care industry. The nation’s leading newspapers and television networks scrambled to provide coverage of the significant findings.

Although the abbreviated versions that made the headlines contained accurate information, the study outcomes and their implications were oversimplified and over-interpreted. Readers and viewers came away thinking that an inexpensive, 50-year-old drug, commonly known as a diuretic (“water pill”), worked for everyone as well as the newer, more expensive drugs for hypertension. Following this thread, some reporters and their interviewed subjects implicated the pharmaceutical industry as a villain for its role in developing and marketing the alternative drugs for the treatment of hypertension. cialis professional 20 mg

Now that experts in the field of hypertension have had time to evaluate the voluminous ALLHAT report, they have begun to question the strength of the study’s design, the accuracy of the conclusions, and the flamboyant character of the researchers’ announcement to the press. Adding to the confusion, a similar, large-population study reported contradictory findings in February 2003, casting doubt on the validity of claims made by the ALLHAT researchers.

This article does not seek to diminish the relevance or importance of ALLHAT but attempts to approach the findings in the context of the entire body of relevant hypertension research, current clinical practice, and existing national guidelines. The reality is that diuretics already top the list of recommended first-line pharmaceutical treatments for hypertension; for most patients, however, diuretics alone are ineffective in lowering and maintaining acceptable blood pressure levels over time. It often becomes necessary to add another type of antihypertensive drug or, in some cases, to switch to a different class of drug.


Initiated in 1994, ALLHAT was one of the first major comparative studies to include clinical outcomes. The following features were considered to be its strengths:

  • sponsorship by the National Heart, Lung, and Blood Institute
  • its broad scope (in comparing one drug from each of four major antihypertensive drug classes)
  • the selection of a low-dose diuretic as standard, or control, treatment
  • its double-blind design, large sample size, and sufficient duration (more than 40,000 high-risk hypertensive patients were to be treated for four to eight years)
  • the selection of trial outcomes (all major vascular complications of hypertension)
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ALLHAT sought to learn whether differences existed among the available antihypertensive agents in reducing the risk of cardiovascular disease. The study compared the effectiveness of a single, low-dose diuretic (chlorthalidone) with that of one drug from each of three newer drug classes: angiotensin-converting enzyme (ACE)-inhibitors, alpha blockers, and calcium-channel blockers.