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Clinical trials: Evidence and unanswered questions--hypertension
1Department of Cardiology, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW 2050, Australia. davidc@card.rpa.cs.nsw.gov.au
Insights
Lowering high blood pressure effectively prevents strokes. While various antihypertensive drugs work, ongoing trials aim to determine the optimal treatment for different patient groups.
Area of Science:
- Cardiovascular Medicine
- Neurology
- Clinical Trials
Background:
- Established efficacy of blood pressure lowering for primary stroke prevention since HDFP and MRFIT.
- Extensive clinical trials confirm benefits across hypertension severity and in elderly with isolated systolic hypertension.
- Emerging evidence supports interventions in normotensive patients with prior stroke or cardiovascular disease.
Purpose of the Study:
- To review the established benefits of antihypertensive therapy for stroke prevention.
- To highlight remaining questions regarding optimal drug selection and combinations.
- To identify the need for comparative trials to guide treatment decisions.
Main Methods:
- Review of over 30 large clinical trials on hypertension and stroke prevention.
- Analysis of evidence for various antihypertensive drug classes (diuretics, beta-blockers, CCBs, ACE inhibitors).
- Consideration of ongoing comparative trials, such as ASCOT.
Main Results:
- Blood pressure reduction is a proven primary prevention strategy for stroke.
- Treatment benefits are observed across all hypertension severities and in elderly patients.
- Evidence is growing for benefits in specific normotensive populations.
Conclusions:
- Antihypertensive therapy is crucial for primary and secondary stroke prevention.
- Optimal drug choice and combination therapy remain key unanswered questions.
- Comparative trials are essential to determine the best antihypertensive regimens for specific patient profiles.
Abstract:
Since the pioneering publications of the Hypertension Detection and Follow-up Program (HDFP) and the Multiple Risk Factor Intervention Trial (MRFIT) in the late 1970s and early 1980s, it has become established that lowering blood pressure in high-risk patients is a highly effective form of primary prevention for stroke. Over the subsequent 25 years, over 30 large clinical trials have extended these initial observations to allow us to conclude that treatment of mild, moderate or severe hypertension, and isolated systolic hypertension in the elderly, all produce important absolute benefits. In addition, excellent specific evidence of benefit is now accumulating for certain groups of normotensive patients, including those with previous stroke, and those with established cardiovascular disease. Although the importance of vigorous antihypertensive therapy for the primary and secondary prevention of stroke is increasingly clear, a large number of unanswered questions remain. For example, while it is apparent that diuretics, beta-blockers, calcium channel blockers (CCBs) and angiotensin-converting enzyme (ACE) inhibitors are all effective antihypertensive agents, the question remains as to which drug, or combination of drugs, is best for which patients. The results of several ongoing comparative trials of different drug regimens, including the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT), may elucidate this further.