Risk Score for Predicting Stroke or Death in New-Onset Atrial Fibrillation Patients: The Framingham Heart Study - Risk Score for Predicting Stroke or Death in New-Onset Atrial Fibrillation Patients: The Framingham Heart Study

Description:

The goal of the study was to develop a risk score for predicting stroke alone and another for stroke or death among patients with new-onset atrial fibrillation (AF) in a community-based study.

Study Design

Study Design:

Patients Enrolled: 868
Mean Follow Up: mean follow-up 4.3 years (4.0 years free of warfarin use)
Mean Patient Age: mean age 75 years
Female: 47%

Patient Populations:

Participant in the Framingham Heart Study who had new onset AF; and age 55-94 years when AF was diagnosed

Exclusions:

AF prior to the first Framingham examination in the offspring cohort or prior to 1960 in the original cohort; missing covariate data; stroke, TIA, or death within 30 days of AF diagnosis; or rheumatic mitral stenosis

Primary Endpoints:

Stroke alone; and stroke or death

Drug/Procedures Used:

Participants in the Framingham Heart Study who had new onset AF (n=868) were included in the study. Baseline risk factor covariates were evaluated in a multivariate model in the 705 participants who were not treated with warfarin at baseline, and the covariates that remained associated with stroke alone and stroke or death were used to create the risk scores.

Principal Findings:

Stroke alone occurred in 83 participants and stroke or death occurred in 382 participants during the mean 4.0-year follow-up. The risk score for stroke included the following: advancing age (0-10 points), female gender (6 points), increasing systolic blood pressure (0-4 points), prior stroke or transient ischemic attack (TIA) (6 points), and diabetes (5 points).

The stroke risk score point range is 0-31, and can be used to evaluate the predicted five-year risk of stroke in the table included in the manuscript (e.g., 5% risk of stroke with risk score 0-1; 75% risk of stroke with risk score 31). The predicted five-year stroke rate with the risk score was ≤7.5% in 14.3% of the cohort (average annual rate ≤1.5%), and ≤10% in 30.6% of the cohort (average annual rate of ≤2%); actual stroke rates were 1.1 and 1.5 per 100 person-years, respectively.

In addition to age, systolic blood pressure, and diabetes, the stroke or death risk score included prior chronic heart failure or myocardial infarction (6 points), smoking (5 points), significant murmur (4 points), and left ventricular hypertrophy (2 points). The c-statistic for the stroke risk score model was 0.66, and for the stroke or death model was 0.70.

Interpretation:

Among patients with new-onset AF in a community-based study, a risk score of baseline characteristics was developed to predict stroke and stroke or death, which may be useful in evaluating treatment options, including warfarin therapy, and identifying very low and very high risk patients.

While other studies have developed risk stratification scores in AF patients, this is the first study to use a community-based cohort, the Framingham Heart Study. Other scores have been derived from patients enrolled in randomized trials, a generally healthier and lower risk population. The present risk score remains to be validated in an independent cohort.

References:

Wang TJ, Massaro JM, Levy D, et al. A risk score for predicting stroke or death in individuals with new-onset atrial fibrillation in the community: the Framingham Heart Study. JAMA 2003;290:1049-56.

Clinical Topics: Anticoagulation Management, Heart Failure and Cardiomyopathies, Prevention, Acute Heart Failure, Smoking

Keywords: Hypertrophy, Left Ventricular, Stroke, Myocardial Infarction, Ischemic Attack, Transient, Follow-Up Studies, Warfarin, Coronary Disease, Blood Pressure, Risk Factors, Smoking, Heart Failure, Diabetes Mellitus


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