Related Experiment Videos
The problems of morbidity and therapy in borderline hypertension
Insights
This feasibility study demonstrated that recruiting and managing patients for a hypertension trial is possible. Selected drugs effectively lowered blood pressure, with no increased psychological stress observed in participants.
Area of Science:
- Cardiovascular medicine
- Clinical trial methodology
- Public health
Background:
- Hypertension management is crucial for reducing morbidity and mortality.
- Previous studies indicated a need for large-scale trials to establish effective treatment protocols for diastolic pressures between 90-109 mm Hg.
Purpose of the Study:
- To assess the feasibility of a large-scale hypertension intervention trial.
- To evaluate the acceptability of trial participation for asymptomatic individuals and their physicians.
- To determine the efficacy and safety of bendrofluazide and propranolol in controlling diastolic blood pressure.
- To examine the psychological impact of trial participation.
- To identify cost-effective recruitment and supervision strategies.
Main Methods:
- Recruited over 1500 adults aged 35-64 with diastolic pressures of 90-109 mm Hg.
- Utilized family practices with supporting staff for recruitment and screening.
- Administered bendrofluazide and propranolol, comparing outcomes to a placebo group.
- Assessed blood pressure control, side effects, and psychological well-being.
Main Results:
- Achieved recruitment and feasibility objectives with a 13% dropout rate over 2.5 years.
- Bendrofluazide and propranolol significantly reduced blood pressure compared to placebo.
- No increased psychological stress was noted; participants with initial symptoms showed improvement.
- Family practice-based recruitment and supervision proved effective.
Conclusions:
- A large-scale trial to improve morbidity and mortality in patients with diastolic hypertension is feasible.
- Bendrofluazide and propranolol are effective in lowering blood pressure with acceptable side effect profiles.
- Expansion of the trial to the target sample size of 18-36,000 subjects is recommended for statistically significant endpoint data.
Abstract:
The aim of the trial was to see whether it was possible to improve morbidity and mortality in both males and females with diastolic pressures between 90 and 109 mm Hg. The initial calculations suggested that it would be necessary to screen between 250-500,000 people to obtain 18-36,000 subjects. This was the number predicted to obtain a statistically significant end-point on current knowledge of morbidity and mortality in this age range. The initial aim was to mount a trial of feasibility with the following objectives: (1) To recruit up to 1000 adults of both sexes aged 35 to 64 years with diastolic pressures in the 90-109 mm Hg range. (2) To determine the acceptability of the trial to asymptomatic subjects as well as their physicians. (3) To show that selected drugs (bendrofluazide and propranolol) adequately control pressure without undue side-effects. (4) To assess the psychological effects of inclusion in the trial. (5) To examine the cost and efficiency of different types of recruitment and supervision. These objectives have now been largely achieved with over 1500 subjects in the study at 2 1/2 years and a drop-out rate of about 13% in all. It appears that the best method of recruitment and supervision is through family practices with supporting staff, particularly in the screening phase. Both the selected drugs reduce the blood pressure significantly and although the placebo groups also show a maintained fall of pressure, the difference from the treated groups is significant. There is no evidence of increased psychological stress by inclusion in the trial and those with psychological symptoms at the outset improve in comparison with their control subjects outside the trial. In order to reach an end-point which will give data of statistical significance, the trial should now be expanded as rapidly as possible towards the goal of recruiting 18-36,000 subjects.