 The ALLHAT was a randomized, double-blind, multicenter clinical institutional trial, entirely sponsored by the National Heart, Lung, and Blood Institute NHLBI 3, and designed to determine whether occurrence of fatal or nonfatal coronary heart disease is lower for high risk hypertensive patients treated with amlodipine, lisinopril, doxazosin, or chlorthalidone. The protocol was also approved by an independent Review Committee external to the NHLBI 7. The ALLHAT recruited 9,000-15,000 participantsintervention arm total: 33,357, and the follow-up was quite long 4-8 years. The doxazosin arm was closed prematurely because of higher mortality 8. Despite a number of important limitations of this study 4,9, the overall impact of its findings remains very high. 