Epidemiology of heart failure

Abstract

Analysis of 34 years of follow-up of Framingham Study data provides clinically relevant insights into the prevalence, incidence, secular trends, prognosis, and modifiable risk factors for the occurrence of heart failure in a general population sample. Heart failure was found to be highly prevalent, affecting about 1% of persons in their 50s and rising progressively with age to afflict 10% of persons in their 80s. The annual incidence also increased with age, from about 0.2% in persons 45 to 54 years, to 4.0% in men 85 to 94 years, with the incidence approximately doubling with each decade of age. Women lagged slightly behind men in incidence at all ages. Male predominance was because of a higher rate of coronary heart disease, which confers a fourfold increased risk of heart failure. Heart failure, once manifest, was highly lethal, with 37% of men and 33% of women dying within 2 years of diagnosis. The 6-year mortality rate was 82% for men and 67% for women, which corresponded to a death rate fourfold to eightfold greater than that of the general population of the same age. Sudden death was a common mode of exitus and accounted for 28% of the cardiovascular deaths in men and 14% in women with heart failure. Hypertension and coronary disease were the predominant causes for heart failure and accounted for more than 80% of all clinical events. Factors reflecting deteriorating cardiac function were associated with a substantial increase in risk of overt heart failure. These include low vital capacity, sinus tachycardia, and ECG evidence of left ventricular hypertrophy. Modifiable predisposing risk factors for heart failure include hypertension, impaired glucose tolerance, an elevated total to high-density lipoprotein cholesterol ratio, obesity, and cigarette smoking. In subjects with coronary disease risk increases progressively from angina to recognized myocardial infarctions to unrecognized infarctions in men. In women angina also carried half the failure risk of a myocardial infarction, and in both sexes unrecognized infarctions were at least as dangerous as symptomatic ones. Using simple office procedures and laboratory tests, it is possible to identify high-risk candidates for heart failure early in its course for preventive management before irreversible myocardial damage has occurred.