ALLHAT in perspective: implications to clinical practice and clinical trials

ALLHAT study is the biggest randomized clinical trial in hypertension ever conducted. Its objective was to ompare the efficacy of newer (calcium channel blocker amlodipine and angiotensin-converting enzyme inhibitor inopril) to the older (diuretic chlorthalidone) antihypertensive agents in the treatment of patients with hypertension. After enrolling 42,000 patients who were followed for an average of 4.9 years, ALLHAT did not find significant differences in the primary end-points between these antihypertenive agents. ALLHAT however found significant differences in the secondary end-points such as heart failure and strokes between chlorthalidone and amlodipine or lisinopril. Based on these and on economic reasons, the investigators unequivocally recommended diuretics as the first line therapy for hypertension. Since its publication, ALLHAT has been much discussed, debated A and opined. The choice of drugs for study, the study design, the conduct of the study and the conclusions drawn by the investigators had all been criticised or controversial. Yet ALLHAT has been widely quoted, commented upon or referred to and it has been instrumental in initiating the JNC VII Guidelines. Thus a thorough understanding of ALLHAT is necessary for clinical practice and in designing and evaluating clinical trials in the future. Moving Points: in Medicine will capture the essence of ALLHAT, discusses its implications to clinical trials and explores its possible impact on the practice of medicine in this country.