Individualization of antihypertensive treatment: theory and practice

Besides the selection of the drug which is likely to be the most effective, the concept of individualization of antihypertensive treatment includes the precise assessment of each individualʹs absolute cardiovascular risk. The classical practice of cardiovascular medicine places subjects above or below the thresholds of specific biological values, according to Expert Committee Recommendations, based on the results of prospective studies and placebo-controlled large scale therapeutic trials. A blood pressure level above mmHg, a plasma cholesterol level above 2.5 g/l, a blood glycemia above 1.4 g/l, transform a subject into a patient. Treatment is proposed to the “labelled” subject, on the evidence of a 10-40% statistically significant reduction of the relative risk of cardiovascular or renal event, within a certain time interval. The actual information that subjects would like to obtain from physicians is indeed their individual absolute risk of suffering a cardiovascular event (1 to 99% “chance”) within the next few years, and the absolute benefit which is likely to be offered by the medical intervention. This new decision-making process requires the physicianʹs utilisation of multivariate equations which more accurately predict the risk than the limited information provided by the measurement of a single risk factor. It implies a shared decision by the physician and his/her informed patient about the need for treatment. This approach is expected to be cost-effective for both individuals and populations. The main limitations of this approach are 1) the ability of physicians to reduce the variability in their prognostic performance through easy access to micro-computers 2) the internal and external validity of these equations, derived from data collected at certain time points in a single population 3) the great number of unknown variables which determine the inter-individual variability in cardiovascular risk, especially genetic background 4) the need for introducing measurements of preclinical disease such as left ventricular hypertrophy, vascular wall enlargement and microproteinuria which are more closely related to cardiovascular events than classical risk factors, although they may only succeed in providing a minimal improvement in prognosis accuracy at an unacceptable cost.