5-year risk of stroke or death
Measured Factor Detail
The Framingham score estimates the risk of stroke or death in a 5-year time period in patients with new-onset atrial fibrillation (AF). The score utilizes age, systolic blood pressure (SBP), prior myocardial infarction or congestive heart failure, smoking status, left ventricular hypertrophy (LVH), and diabetes as predictors. Each factor is weighted differently in a point scale, once the data is collected all the points are added together and matched to the corresponding percentage. Patients who are younger than 55 years, have a SBP<120 mmHg, no diabetes, no prior myocardial infarction or congestive heart failure, and do not smoke have a 5-year risk of 8%. Meanwhile patients who are 55 years or older and have other comorbidities have a higher risk, with the cutoff point being a 5-year risk greater than 80%.
Measured Factor Low Impact
- Low risk of stroke or death in 5 years
Measured Factor High Impact
- High risk of stroke or death in 5 years
- Critical High: 5-year risk > 80%
- Normal: 5-yeark Risk < 8%
- Normal Adult Male: 5-year risk < 8%
- Normal Adult Female: 5-year risk < 8%
- Normal Geriatric Male: 5-year risk 8-80%
- Normal Geriatric Female: 5-year risk 8-80%
An important limitation of this scoring system is the era of clinical care the patients in the study were from. These patients were from a clinical care era in which no statins, angiotensin-converting enzyme inhibitors or beta blockers existed, therefore their outcomes could have been affected, especially the risk of death.
Study Validation 1
Prospective, observational cohort study in Framingham, Massachusetts aimed at deriving risk scores for stroke alone and stroke or death in community-based patients with new onset atrial fibrillation (AF). The study population consisted of the original cohort of people used in the Framingham Heart Study and their offspring. Inclusion criteria included patients diagnosed with AF between the ages of 55 and 94. Baseline risk factors were collected and included mean blood pressure values of 2-physician obtained measurements and diabetes defined by a fasting blood glucose of at least 140 mg/dL or use of insulin or hypoglycemic medications. Primary outcomes measured were stroke alone and the combination of stroke or death. Risk scoring system for each outcome was developed and points were assigned to each risk factor. The study also evaluated if the risk score had the ability to identify low-risk participants using the following thresholds of 5-year stroke risk: 10% (average annual rate 2%), 7.5% (average annual rate 1.5%) and 5% (average annual rate 1%). Patients were followed up for 4 years, stroke alone occurred in 83 patients and stroke or death occurred in 382 patients. Based on the study a risk score was developed with the following predictors; advancing age, female sex, increasing systolic blood pressure, prior stroke or transient ischemic attack, and diabetes. Using this risk score, 14.3% of patients had a 5-year predicted risk rate ≤ 7.5% and 30.6% of patients had a predicted 5-year risk rate ≤ 10%. Researchers concluded this risk score was appropriate to estimate the absolute risk of adverse events in patients with newly diagnosed AF.
Study Additional 1
Editorial article discussing different aspects of stroke prevention in patients with atrial fibrillation. Atrial fibrillation (AF) is a common problem in older patients and one of the most important problems associated with it is the risk of ischemic stroke. Patients with AF have a 4 to 5-fold increase risk of ischemic stroke, therefore it is important to begin preventative therapies in these patients, however doing so remains a major challenge. This article mentions the Framingham risk score as an important tool to determine which patients would benefit the most from preventative therapy. The risk score is based on 5 risk factors; advancing age, female sex, increasing systolic blood pressure, prior stroke or transient ischemic attack, and diabetes mellitus. Determining which patients should receive oral anticoagulation therapy with warfarin is always difficult, however this risk score can help clinicians and patients make that decision. Warfarin is one of the most popular medication used as anticoagulation therapy, but it is a difficult medication to control due to the therapeutic window it requires and it also has a high risk of bleeding. As a result, using risk stratification scores can help identify patients who have the best chance of benefit from oral anticoagulant therapy.