An epidemiologic perspective of systemic hypertension, ischemic heart disease, and heart failure.

Improvements in the identification and control of hypertension have helped define populations at risk for hypertension and delineated the role of hypertension as a risk factor in ischemic heart disease and heart failure. Epidemiologic data document the high prevalence of hypertension among the elderly and black populations. Beginning in the 1970s, a new perspective on the identification and treatment of hypertension began to emerge with greater emphasis on blood pressure control, particularly among these high-risk groups. By the early 1990s, most hypertensive individuals were being treated and blood pressure was under control in 55% of hypertensive persons overall. Although the importance of elevated diastolic pressure has traditionally been emphasized, in recent years the clinical implications of isolated systolic hypertension and the benefit of treating elevated systolic pressure have been recognized. Coronary heart disease is associated with definite hypertension (> or =160/95); however, the presence of other risk factors such as elevated plasma levels of cholesterol and high-density lipoprotein cholesterol, cigarette smoking, and diabetes mellitus create a synergy with even mild hypertension (140-159/90-94 mm Hg) to increase coronary risk. A different situation is present for cardiac failure. Data from the Framingham Heart Study demonstrate that hypertension, myocardial infarction, angina pectoris, diabetes mellitus, left ventricular hypertrophy, and valvular heart disease were associated with an increased relative risk for cardiac failure. The relative risk for cardiac failure was greatest for persons with a previous myocardial infarction, and hypertension and previously diagnosed coronary heart disease were important precursors of cardiac failure.