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Background: Increasing concern over long-term drug treatment of mild hypertension has stimulated several studies of weight reduction. Phase I of the Trial of Antihypertensive Interventions and Management demonstrated a short-term effect of weight loss on blood pressure control in overweight persons with mild hypertension, who were either taking placebo or taking low-dose monotherapy. Phase II investigates the long-term benefit of weight loss on the ability to maintain blood pressure control. Methods: From 10 148 community-based screenees, 587 persons (5.8%), aged 21 to 65 years, entered a multicenter, randomized drug (double-blind, placebo-controlled) and diet trial. Participants had a diastolic blood pressure between 90 and 100 mm Hg and were at 110% to 160% of their ideal weight. They were randomized to a usual diet (n=296) or to a weight loss diet (n=291) and within each diet group to placebo, chlorthalidone, 25 mg/d, or atenolol, 50 mg/d. Treatment failure was defined as using additional antihypertensive medications if diastolic blood pressure rose above 90 mm Hg according to protocol-specified criteria. Results: At baseline, mean diastolic blood pressure was 93 mm Hg; systolic blood pressure, 143 mm Hg; weight, 88 kg; percent ideal weight, 137%; age, 48 years; 56% were men; and 33% were black. Mean follow-up was 4.5 years. There was a net loss of 2 to 3 kg with weight loss diet compared with usual diet over most of the follow-up period. The 5-year incidence of treatment failure was 56.7 per 100 participants with usual diet and 49.8 per 100 with weight loss. Long-term weight loss decreased failure of blood pressure control for those receiving placebo or low-dose diuretic or [Beta]-blocker by 23%. The results were similar in direction in each drug group. Conclusions: The Trial of Antihypertensive interventions and Management demonstrated that weight reduction is an effective long-term therapy for maintaining blood pressure in the normal range when used as monotherapy or in combination with either thiazide diuretics or [Beta]-blockers. Consequently, weight loss should be recommended for the management of obese individuals with mild hypertension. (Arch Intern Med. 1993;153:1773-1782)

* This report examines the effect of weight loss, alone and in combination with drugs, on diastolic blood pressure change in the Trial of Antihypertensive Interventions and Management (TAIM), which is a randomized, multicenter, placebo-controlled clinical trial of drug and diet combinations in the treatment of mild hypertension among 787 patients. Diastolic blood pressure drop (11.6 mm Hg) at 6 months among those patients who were randomized to weight reduction and placebo drug treatment was greater among those who lost 4.5 kg or more, than the 7-mm Hg drop for those who lost less than 2.25 kg or for the placebo-treated control group, and it was statistically equivalent to the reduction achieved by 25 mg of chlorthalidone or 50 mg of atenolol (11.1- and 12.4-mm Hg drop, respectively). Weight loss potentiated effects of drugs, with reductions of 18.4 mm Hg, for those patients who were taking atenolol and had a 4.5-kg or more weight loss, and of 15.4 mm Hg, for those patients who were taking chlorthalidone and had at least a 2.25-kg weight loss. We concluded that effective weight loss ([Mathematical Expresssion Omitted] 4.5 kg) lowers blood pressure similarly to low-dose drug therapy and potentiates drug effects, with the apparent 4.5-kg threshold being lowered to 2.25 kg for those patients who receive chlorthalidone. (Arch Intern Med. 1992;152:131-136)