McClure LA, Kleindorfer DO, Kissela BM, Cushman M, Soliman EZ, and Howard G. Assessing the Performance of the Framingham Stroke Risk Score in theReasons for Geographic and Racial Differences in Stroke Cohort. Stroke. 2014
Vivek Rai, MD
The most well-known and therefore widely used stroke risk score is Framingham Stroke Risk Score, which was developed in 1990’s. Other tools have been offered recently for risk stratification, such as ASCVD and CHS risk score, but FSRS remains the standard for predicting stroke risk in general population. FSRS and other risk scores do not account for impact of race because the study population had few black participants. Reasons for Geographic And Racial Differences in Stroke (REGARDS) study assessed the performance of FSRS in both blacks and whites.
The REGARDS study used national population based cohort that recruited 30,239 participants of 45 years of age or older, with 45% male and 55% female; 42% black and 58% white between 2003 and 2007. McClure and colleagues compared the observed stroke rates to that predicted by FSRS in 27,748 stroke-free at baseline participants who were followed for an average of 5.6 years. The authors report that FSRS accurately predicted higher stroke rate in patients deemed to be at higher risk due to presence of traditional risk factors such as age, sex, diabetes, smoking etc. but also that FSRS overestimated the risk by about 2 times in all race-sex strata. The overestimation was consistent in subgroups of FSRS risk factors and was highest among those with highest risk.
This very interesting study reinforces the validity of FSRS in predicting stroke risk but also shows that FSRS may be overestimating risk in today’s population. The reasons for this overestimation may lie in the study itself (such as only 5.6 years of follow up period is used to determine 10-year stroke risk) or may reflect decreasing incidence of stroke due to better (as compared to 1990’s) primary prevention. I think the study points towards a valid concern that the tools developed for risk assessment over 20 years ago may not be entirely accurate today and as such future research should be directed towards estimating the stroke risk more accurately, which is important for research planning and stroke prevention in community.