Abstract 13293: High Sensitivity C-reactive Protein and the Risk of Stroke in Atrial Fibrillation: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study
Background Improved strategies are needed to identify persons with atrial fibrillation (AF) at high risk for stroke. Previous studies implicate inflammation as a trigger for thrombus formation in the fibrillating atria. We hypothesized that elevated levels of high sensitivity C-reactive protein (hs-CRP), a marker of inflammation, would be associated with stroke in participants with AF in the REGARDS cohort.
Methods A total of 30239 participants (41% African American, 55% female, age > 45 years), of whom 2603 had AF, were examined. AF was ascertained by ECG or self- reported history of previous physician diagnosis. Stroke cases were identified and adjudicated during median follow-up of 5.1 years. Cox proportional hazard analysis was used to examine the risk of stroke in study participants stratified according to the presence or absence of AF at baseline.
Results Median hs-CRP was 2.7 mg/L (IQR 5.0) in the AF group and 2.2 mg/L( IQR 4.0) in the group without AF (p <0.0001). A total of 767 strokes occurred during follow up of which 118 were in the AF group. In participants with AF, 1 mg/L difference in hs-CRP was not associated with subsequent stroke before adjustment (HR 0.999, 95% CI 0.978-1.020) and after adjustment for age, sex, CHADS2 variables and warfarin use (HR 1.001, 95% CI 0.981-1.022). In participants without AF, CRP was predictive of stroke before adjustment (HR 1.012, 95% CI 1.008-1.016) and after adjustment for age, race, sex, CHADS2 variables and warfarin use (HR 1.011; 95% CI 1.007-1.016). Similar results were obtained using log (hs-CRP) and when comparing stroke rates in the top vs. bottom quartiles of hs-CRP.
Conclusion In the REGARDS cohort, hs-CRP is predictive of stroke in individuals without AF but not in those with AF. The findings suggest a limited role of hs-CRP in the current stoke prediction schema in subjects with AF such as CHADS2.
- © 2012 by American Heart Association, Inc.