Control of moderately raised blood pressure. Report of a co-operative randomized controlled trial.

A study was designed to investigate the effect on morbidity and mortality of lowering diastolic blood pressure levels of between 100 and 120 mm Hg to below 100 mm Hg. Fifty-eight men and women, aged from 45-69 years, with blood pressure levels between 100 and 120 mm Hg were matched for age, sex, and blood pressure levels with 58 control patients. The maintenance of diastolic blood pressures at levels below 100 mm Hg was successfully carried out without serious drug side effects. Treatment effectively maintained diastolic pressures below 100 mm Hg, but no effect was shown on other terminating events. Few problems were found in the management of patients with minimally raised blood pressure, most of whom were symptom-free. The treatment and control groups became less comparable as increasing numbers of patients in the control group were withdrawn from the trial as diastolic pressures rose above 130 mm Hg.