Absolute cardiovascular risk: the basis for deciding to treat.

It has been convincingly demonstrated that a raised blood pressure is a risk factor for cardiovascular disease and that its reduction saves lives. It seems logical to suggest that the whole population's blood pressure distribution should be displaced downwards, since the reduction of blood pressure by only a few millimeters of mercury, if easily and safely achieved, would produce more disease prevention than could be attained by any other conceivable clinical strategy. Physicians already have powerful tools to lower blood pressure in individual patients, but must make challenging decisions as to when and how to use them. Blood pressure level is a reflection of relative risk and one of many risk factors that determine absolute risk. Reduction of blood pressure therefore does not cure cardiovascular disease, but reduces the risk of developing disease. The need for hypotensive therapy should be determined by absolute risk and the opportunity for successful prevention, rather than by a threshold level of blood pressure. The task of the physician is to assist the patient in assessing the balance between the potential for benefit and the burden of intervention, and to provide the best possible care to implement the therapeutic choice that is made.