Introduction: The ability to identify a stroke/TIA-free population at high risk for stroke is important for risk assessment in the general population, and also a critical step to make a primary stroke prevention trial feasible. The standard for risk stratification is the Framingham Stroke Risk Score (FSRS); however, its use requires a clinic visit for blood pressure and ECG assessment, and laboratory measurement of glucose levels. The feasibility of a primary prevention trial would be greatly enhanced by a brief interview, potentially conducted over the telephone or web, to identify a high-risk population.
Methods: A general population sample consisting of 23,983 REGARDS participants aged 45+ who reported being stroke and TIA free at baseline was characterized on 11 self-reported characteristics: age, race, sex, self-reported diagnosis of medical conditions (hypertension, diabetes, atrial fibrillation, and myocardial infarction), smoking, previous stroke symptoms, self-reported general health, and education. Participants were followed for incident stroke, with associations assessed by proportional hazards.
Results: Over an average follow-up of 8.2 years, 564 incident strokes occurred. The self-reported characteristics were strongly related to stroke risk (see table), and proved marginally more predictive of stroke risk (c-statistic = 0.7268; 95% CI: 0.7078 - 0.7459) than the FSRS (c-statistic = 0.7222; 95% CI: 0.7025 - 0.7419). The annual stroke risk was 1.4% (95% CI: 1.2 - 1.7) for those in the highest decile of the telephone risk score. The Spearman correlation between the FSRS and the REGARDS telephone risk score was 0.848 (95% CI: 0.844 - 0.851).
Discussion: The REGARDS Telephone Stroke Risk Score can be calculated using data collected over the telephone, at a web site, or in person. It can identify a population at high risk for stroke as well as the FSRS clinic-based assessment can, making it an efficient stroke risk assessment tool.