The risk of hypertension: successes and failures of antihypertensive treatment.

All the antihypertensive trials that have compared active treatment with placebo have given similar and, at the same time, different results. In all trials the therapeutic quotient is above 1, indicating that in all trials mortality and morbidity may be lower (by at least 20%) in the actively treated group. However, the prevented event rate, an absolute measure of benefit, indicates a very large benefit (24 events prevented every 100 patient-years) in the trials involving severe hypertension, and a quite small rate (0.15 event prevented every 100 patient-years) in the MRC mild hypertension trial. Although, taken as a whole, the results of treatment of mild hypertension may appear only moderately encouraging, a considerably greater benefit is observed when a mildly elevated diastolic blood pressure is associated with other risk factors, such as the male sex, cigarette smoking, high blood cholesterol level and elevated systolic blood pressure. Emphasis has been placed, in recent years, upon other limitations in the success of antihypertensive therapy, and it has been stressed that the very effective prevention of cerebrovascular events in the treated hypertensive has not been matched by an equally effective prevention of coronary events. It has also been shown that the risk in treated hypertensives remains higher than that of the general population. Understanding the limitations of current antihypertensive therapy may help in extending treatment successes in the future. A hypothesis that has been recently advanced is that some of the failures of antihypertensive therapy may result from excessive lowering of blood pressure especially in hypertensive patients with ischaemic heart disease (the problem of the 'J'-shaped curve).(ABSTRACT TRUNCATED AT 250 WORDS)