ORIGINAL INVESTIGATION Profile for Estimating Risk of Heart Failure William B. Kannel, MD, MPH; Ralph B. D’Agostino, PhD; Halit Silbershatz, PhD; Albert J. Belanger, MS; Peter W. F. Wilson, MD; Daniel Levy, MD Context: We devised a risk appraisal function to assess pacity or chest x-ray film because these may not be readily the hazard of heart failure in persons who are predis- available in some clinical settings. posed by coronary disease, hypertension, or valvular heart disease. Results: Using the risk factors that make up the multi- variate risk formulation—derived from ordinary office Objective: To provide general practitioners and intern- procedures—the probability of developing heart failure ists with a cost-effective method to select people at high can be estimated and compared with the average risk for risk who are likely to have impaired left ventricular sys- persons of the same age and sex. Using this risk profile, tolic function and may therefore require further evalu- 60% of events in men and 73% in women occurred in ation and aggressive preventive measures. subjects in the top quintile of multivariate risk. Methods: The routinely measured risk factors used in Conclusions: Using this multivariate risk formula- constructing the heart failure profile include age, elec- tion, it is possible to identify high-risk candidates for trocardiographic left ventricular hypertrophy, cardio- heart failure who are likely to have a substantial yield megaly on chest x-ray film, heart rate, systolic blood pres- of positive findings when tested for objective evidence sure, vital capacity, diabetes mellitus, evidence of of presymptomatic left ventricular dysfunction. The myocardial infarction, and valvular disease or hyperten- risk profile may also identify candidates who are at sion. Based on 486 heart failure cases during 38 years of high risk for heart failure because of multiple, mar- follow-up, 4-year probabilities of failure were com- ginal risk factor abnormalities that might otherwise be puted using the pooled logistic regression model for each overlooked. sex; a simple point score system was employed. A mul- tivariate profile was also produced without the vital ca- Arch Intern Med. 1999;159:1197-1204 EART FAILURE morbidity high-risk, asymptomatic persons with hy- and mortality continue pertension, coronary disease, left ventricu- unabated despite de- lar hypertrophy (LVH), diabetes, and val- clines in some cardiovas- vular heart disease. High-risk candidates cular events.1 Heart fail- for heart failure need to be targeted for Hure is a progressive, often terminal stage evaluation and treatment in a cost- of cardiac disease that, when symptom- effective manner. Their evaluation and atic, curtails survival like many types of treatment should be designed to delay the cancer.2 In Framingham Study subjects onset of heart failure, since treatment of with overt congestive heart failure, the me- asymptomatic persons with impaired left From the Department of dian survival rate was only 1.7 years for ventricular systolic function has been Preventive Medicine and men and 3.2 years for women.3 This heart shown to delay the onset of overt heart Epidemiology, Evans 4 Department of Clinical failure mortality rate is 4 to 8 times the failure. Independent predictors of con- Research, Boston University death rate of the general population of gestive heart failure have been identified School of Medicine, Boston, comparable age and has not improved by epidemiological research in the Mass (Drs Kannel, D’Agostino, greatly despite major declines in coro- Framingham Study.2 Using these risk fac- Silbershatz, Wilson, and Levy nary, hypertensive, and rheumatic heart tors, we constructed a multivariable risk and Mr Belanger); and the disease mortality.1 Furthermore, sudden profile that efficiently identifies prime National Heart, Lung, and death continues to be a prominent fea- candidates for heart failure from among Blood Institute, National ture of heart failure.1 those with predisposing conditions. Institutes of Health, Bethesda, Effective prevention of heart failure The purpose of this report is to pro- Md (Drs Wilson and Levy). These authors are affiliated requires the early detection and correc- vide a risk profile for general practition- with the Framingham Heart tion of predisposing conditions and risk ers and internists that will enable them to Study; see the acknowledgments factors in susceptible persons. Preven- estimate the risk of developing heart fail- at the end of this article for tive measures must be implemented by ure in predisposed persons with coro- further information. general practitioners and internists for nary disease, hypertension, or valvular ARCH INTERN MED/ VOL 159, JUNE 14, 1999 1197 ©1999 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 SUBJECTS AND METHODS At each examination, subjects were seated and blood pressures were measured twice by the examining physician using a mercury sphygmomanometer. Hypertension was de- The Framingham Study is a prospective, epidemiological, fined as the presence of either an elevated blood pressure or population-based undertaking designed to investigate the ongoing antihypertensive treatment of a previously elevated prevalence, incidence, and determinants of cardiovascu- blood pressure. Based on 2 physicians’ readings, elevated blood lar disease. The study design, recruitment procedures, popu- pressure was identified when blood pressure was 140/90 lation sampling, response rates, and methodology have been mm Hg or greater on both readings. Persons with an el- reported in detail elsewhere.5-8 Subjects were reexamined evated fasting blood glucose level exceeding 7.8 mmol/L (140 every 2 years for the appearance of cardiovascular events mg/dL) or a casual blood glucose level over 11.1 mmol/L (200 in relation to previous biennially measured risk factors. Each mg/dL) were considered diabetic, as were persons using in- examination included a medical history, physical exami- sulin or oral hypoglycemic agents. Electrocardiographic LVH nation, several blood pressure measurements, a 12-lead elec- was diagnosed when both increased voltage and repolariza- trocardiogram (ECG), and laboratory tests. tion abnormalities were present.5 When the cardiothoracic The probability of developing heart failure was deter- ratio exceeded 0.5 on chest film, cardiomegaly was identi- mined in subjects aged 45 through 94 years who had coro- fied. Vital capacity was measured by spirometry using a Col- nary disease, hypertension, or valvular heart disease, but lins respirometer; the best of 3 efforts was recorded. Body mass were free of the condition at baseline. Over the course of index was defined as weight measured in kilograms divided the 38-year study period, among those with these predis- by square of height in meters. posing conditions, there were 6354 person-examinations A pooled logistic regression model—f(x)=1/ with follow-up in men and 8913 in women. The indepen- (1 + e−x)—was used to generate the heart failure risk pro- dent risk factors used to predict heart failure included age, file9; x was estimated by an equation with an intercept (a), systolic blood pressure, LVH on ECG, vital capacity by spi- and the sum of the b coefficients for each of the specific rometry, heart rate, coronary heart disease, murmurs sig- risk factors multiplied by their actual values. For ex- nifying valvular heart disease, diabetes, radiographic car- ample, x = a +(b1 3age) + (b2 3 LVH) + (b3 3 vital ca- diomegaly, and, in some models, body mass index. pacity) + (b4 3 heart rate) + (b5 3 systolic blood pressure) Definitions and criteria for the categorical risk factors and +(b6 3coronary disease) + (b7 3 valve disease) + (b8 3 cardiac conditions have been reported in detail else- diabetes) + (b9 3 cardiomegaly). This model provides a where.5,6 Active surveillance for development of heart fail- simple formula for estimating the probabilities of heart fail- ure has been a feature of the Framingham Study since its ure when specific risk factors are present. Separate mod- inception. Using information from the Framingham Study els were developed for each sex and for persons with coro- clinic examinations, hospital admissions, and attending phy- nary disease, hypertension, or valvular heart disease. Only sicians’ records, a diagnosis of congestive heart failure was variables with a .05 level of significance in the multivari- designated when at least 2 major or 1 major and 2 minor ate model for the development of heart failure in either sex criteria for heart failure were present (Table 1). Minor cri- were used in the risk functions. Specifically, the logistic teria were accepted only if they could not be attributed to model predicts the probability of developing heart failure another existing medical condition. within the next 4 years based on the presence of the rel- At each examination, interim cardiovascular events evant risk factors specified above. Four years of follow-up were ascertained from medical histories, physical exami- was chosen as the prediction intervention interval; conse- nations, ECGs, chest x-ray films, and review of interim medi- quently, every other interim biennial examination was used. cal records, including the hospital and attending physi- Subjects missing more than 2 biennial examinations were cians’ records of those who failed to reappear for their excluded from the analysis. For those missing up to 2 ex- scheduled biennial examination. All suspected