The original grant from 1990 to 1995 was funded because analyses of clinical trial subgroups had raised the concern that, in patients with high blood pressure, diuretic therapy may increase the risk of sudden cardiac death. Given the size of the hypertensive population in the United States, the prevalence of diuretic therapy for hypertension, and the persistent concerns regarding the relation of diuretic therapy to the risk of primary cardiac arrest (PCA), the study proved to be of particular interest to clinicians, epidemiologists, public policy makers, and the general public.