Recruitment for phase I of the trials of hypertension prevention.

Phase I of the Trials of Hypertension Prevention was a multicenter, randomized, controlled trial designed to determine the efficacy of seven nonpharmacologic interventions in reducing blood pressure among persons with high-normal diastolic blood pressure. The initial goal for recruitment was to enroll 2,100 participants over a nine-month period. The two major strategies for reaching potential participants were direct mailings and work site screenings. The yield from the first screening visit to randomization was 13% overall, with clinic-specific yields ranging from 4.5% to 31.7%. After five months of recruitment, approximately 60% of the goal for that point in the recruitment timetable had been randomized. Clinical centers falling short of their goals at that time altered their recruitment strategies and intensified their efforts, and centers that had exceeded their goals recruited additional participants. As a result, 2,182 participants, or 104% of the goal for recruitment, were randomized over a 13-month period. Those clinics using a cohort, or wave, type of enrollment were most successful in achieving their recruitment goals within the prescribed timetable.

Trial of antihypertensive intervention and management: greater efficacy with weight reduction than with a sodium-potassium intervention.

The Trial of Antihypertensive Intervention and Management evaluated nine diet-drug combinations in 878 mildly hypertensive, moderately obese participants using a 3 x 3 factorial design. Drugs evaluated were placebo, diuretic (chlorthalidone), and beta-blocker (atenolol); diets were usual (no intervention), weight reduction, and low sodium/high potassium (Na/K). This article reports 6-month dietary changes and the effect of dietary change on blood pressure. Six-month mean weight change was -4.7 kg in the weight reduction group, -0.3 kg in the Na/K group, and -0.5 kg in the usual-diet group. At 6 months, daily electrolyte excretion had changed in the Na/K intervention group. Daily sodium excretion decreased from 138.0 to 112.0 mmol in the Na/K group and increased from 134.1 to 138.4 mmol in the weight reduction group and from 129.1 to 137.0 mmol in the usual-diet group. Daily potassium output increased from 58.7 to 71.4 mmol in the Na/K group, from 57.0 to 60.5 mmol in the weight reduction group, and from 55.3 to 59.1 mmol in the usual diet group. Analysis of 3-day food records indicated that sodium intake decreased from 141.1 to 85.8 mmol and potassium intake increased from 76.4 to 90.5 mmol. Our results indicate that the goal for weight reduction was more easily achieved than the goal for electrolyte modification.