Clinical Trials: Evidence and Unanswered Questions – Hypertension

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.