Epidemiology and prevention of cardiac failure: Framingham Study insights

Abstract

The prevalence, incidence, secular trends, precursors and prognosis of cardiac failure (CHF) is investigated over 3 decades of follow-up of 5209 subjects. Some 485 men and women developed first evidence of CHF. Annual incidence increased from 3 per 1000 at ages 35-64 years to 10 per 1000 at ages 65-94 years with a male predominance because of higher rates of coronary disease. Half developing CHF had coronary disease, but only 10% were free of concomitant hypertension. Appearance of coronary disease conferred an 8-fold increased risk of CHF. Hypertension is the dominant precursor of CHF, increasing risk 2-6 fold; 70% had antecedent hypertension. Systolic pressure was more predictive than diastolic. Non-specific S-T and T-wave changes, intraventricular conduction disturbances and left ventricular hypertrophy were powerful predictors, even taking blood pressure into account. Other independent risk factors include: low vital capacity, rapid heart rate, diabetes, cardiac enlargement, overweight (in women), serum cholesterol (in men under 65 years of age), cigarettes, proteinuria and hematocrit. Risk of CHF can be estimated over a 30-fold range from profiles made up of these independent risk factors. A preventive approach is essential. Despite potent glycosides, diuretics, vasodilators and antihypertensive treatment CHF continues to be a lethal end-stage of heart disease with a 50% 5 year mortality rate. Sudden death is a prominent terminal feature occurring at 9 times the general population rate.