Risk stratification in hypertension: New insights from the Framingham Study

Five decades of epidemiologic research have established that blood pressure elevation is a common and powerful contributor to all of the major cardiov ascular diseases, including coronary disease, stroke, peripheral artery dis ease, renal disease, and heart failure. The common variety of hypertension designated benign essential hypertension was not shown to be either benign or essential. Although clinicians favor the diagnosis and treatment of hype rtension in terms of diastolic blood pressure elevation and categoric cut p oints, epidemiologic data show a more important influence of systolic blood pressure, and a continuous, graded influence of blood pressure even within what is regarded as the normotensive range. An important revelation in epidemiologic hypertension research is that hype rtension usually occurs in conjunction with other metabolically linked risk factors; therefore, less than 20% occurs in isolation. The other risk fact ors that tend to accompany hypertension include glucose intolerance, obesit y, left ventricular hypertrophy, and dislipidemia (elevated total, LDL, and small-dense LDL cholesterol levels, raised triglyceride, and reduced HDL c holesterol levels). Clusters of three or more of these additional risk fact ors occur at four times the rate expected by chance. This clustering is att ributed to an insulin resistance syndrome promoted by abdominal obesity. Th e amount of risk factor clustering accompanying elevated blood pressure was observed to increase with weight gain. Based on Framingham Study data the prevalence of insulin resistance syndrome in the general population could b e as high as 22% in men and 27% in women. Risk of coronary disease, the most common and most lethal sequel to hyperte nsion, increased stepwise with the extent of risk factor clustering. Among persons with hypertension, about 40% of coronary events in men and 68% in w omen are attributable to the presence of two or more additional risk factor s. Only 14% of coronary events in hypertensive men and 5% of those in hyper tensive women occurred in the absence of additional risk factors. Other important features of risk stratification of hypertension are the pre sence of an elevated heart rate and left ventricular hypertrophy, and an el evated fibrinogen that often accompany hypertension. Recent population-base d data reported suggest that elevated renin accompanying hypertension may i ndependently enhance the risk of coronary events. Because clustering of other major risk factors with hypertension is the rul e, the prudent physician should routinely screen for the presence of these other factors, Multivariate risk assessment profiles are now available for coronary disease, stroke, peripheral artery disease, and heart failure, to enable physicians to pool all the relevant risk factor information so as to arrive at a composite risk estimate. Hypertensive patients are more approp riately targeted for therapy by such risk stratification and the goal of th e therapy should be to improve the multivariate risk profile. Am J Hyperten s 2000;13:3S-10S (C) 2000 American Journal of Hypertension, Ltd.