Medical Research Council's Treatment Trial for mild hypertension: an interim report

The pilot phase of the British multicentre randomized controlled trial of treatment for mild hypertension has shown: (1) that unselected subjects, aged 35-64 years, with mild hypertension are willing to enter and remain in a long-term trial even though asymptomatic; (2) that the differences of mean systolic and mean diastolic pressure achieved between treated and control subjects is sufficient to produce the expected difference in terminating events with the 18000 patients calculated as needed for the full-scale trial; (3) that side effects with the two selected active primary regimens (bendrofluazide and propranolol) are common but mild (no serious side effects or toxic reactions have been reported); (4) that the work load imposed by the trial, though considerable during screening and the initiation of patients into the trial, can largely be taken by specially trained nursing staff, and when screening is completed the trial does not impose a heavy burden of follow-up examinations; (5) that there are no adverse psychological effects caused by alerting asymptomatic people to their raised pressure and enrolling them into a prolonged programme of clinical attendance; (6) that the total costs of carrying out a full-scale trial--estimated at about lb.2m ($U.S. 4m)--are commensurate with the potential annual savings in health service expenditure whether the trial shows treatment to be effective or unwarranted.