The aim of this study is to address unresolved issues in the long- term therapy of mild hypertension by continuing the treatment and follow-up of participants enrolled in the Trial of Antihypertensive Interventions and Management (TAIM).
T AIM i s a multicenter, randomized, placebo-controlled trial designed to assess the effectiveness of various combinations of pharmacologic and dietary interventions in the treatment of mild hypertension (DBP 90-100 mmHg). The primary endpoint is blood pressure change between baseline and six months. The study consists of a 3 X 3 factorial design wherein participants are randomly allocated to 9 drug-diet treatment groups. Drugs include placebo, diuretic and 1 beta- blocker. Diets are usual, weight loss and low sodium/high potassium (Na+/K+). The basic strategy is to address clinical questions of interest by comparing mean DBP changes of selected diet-drug combinations. Secondary objectives are to assess for each selected combination: 1) changes in serum and urine chemistries; 2) change in quality of life measures and well-being (including assessment of side effects), and 3) change in cardiovascular risk score. In preliminary TAIM analyses, weight loss appears to substantially lower DBP at 6 months when compared to a usual or Na+/K+ diet. There appear to be no blood pressure differences between the Na+/K+ and usual diet groups. In the continuation of TAIM (COTAIM), the weight loss group and a randomly selected half of the usual diet group are to be followed without change to evaluate the long-term efficacy of weight loss in the control of mild hypertension. The weight loss regimen is to be added to the Na+/K+ group and the other randomly selected half of the usual diet group during a six month enrollment period to evaluate possible additive effects of weight loss and sodium restriction in comparison to weight loss alone.
COT AIM proposes to assess the effectiveness of these various treatments by comparing the proportion successful in blood pressure control on initial drug therapy. In addition, changes in cardiovascular risk scores and quality of life indices for selected antihypertensive interventions will be analyzed. The periods of follow-up will average about 5 years for the weight loss-usual diet comparison, including the TAIM follow-up, and 2 years for the weight loss-weight loss/sodium restriction comparison.
