High-Sensitivity C-Reactive Protein and Risk of Stroke in Atrial Fibrillation (from the Reasons for Geographic and Racial Differences in Stroke Study)

The relation between inflammation and prothrombotic state in atrial fibrillation (AF) is well recognized. This suggests a potential role for high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation, in improving prediction of stroke in participants with AF. Cox proportional hazard analysis was used to examine the risk of stroke in 25,841 participants (40% black and 55% women) with and without AF who were enrolled in the Reasons for Geographic and Racial Differences in Stroke study from 2003 to 2007. Baseline AF (n = 2,132) was ascertained by electrocardiogram and self-reported history of previous physician diagnosis. Stroke events were identified and adjudicated during 8.3 years of follow-up. A total of 655 incident strokes occurred during follow-up. In a model adjusted for sociodemographics, traditional stroke risk factors, and use of aspirin and warfarin, higher levels of hs-CRP were associated with increased overall stroke risk (hazard ratio [HR] 1.30, 95% confidence interval [CI] 1.10 to 1.54, and HR 1.06, 95% CI 1.01 to 1.12 for hs-CRP >3 mg/L and per 1-SD increase, respectively). Higher levels of hs-CRP continued to be associated with incident stroke in participants without AF (HR 1.31, 95% CI 1.09 to 1.57, and HR 1.06, 95% CI 1.01 to 1.12 for hs-CRP >3 mg/L and per 1-SD increase, respectively) but not in those with AF (HR 1.22, 95% CI 0.78 to 1.91, and HR 1.01, 95% CI 0.82 to 1.23 for hs-CRP >3 mg/L and per 1-SD increase, respectively). In conclusion, although hs-CRP was significantly associated with stroke risk in this population, it seems to be limited to those without AF. These findings suggest a limited value of hs-CRP in improving stroke risk stratification in subjects with AF.