Abstract 97: The Impact of “Traditional” Risk Factors for Incident Versus Recurrent Stroke
Introduction: Risk factors for incident stroke have been shown to also be associated with risk for recurrent stroke; however, to our knowledge there has not been a cohort with risk factors measured in a sufficient number of stroke-free and prevalent stroke cases to contrast the impact of the risk factors between incident and recurrent stroke.
Methods: REGARDS recruited 30,239 participants between 2003 and 2007. Participants were stratified into those reporting and not reporting a physician-diagnosed stroke at baseline. Proportional hazards analysis was used to assess the role of risk factors for stroke.
Results: Over 6.2 years of follow-up, there were 825 strokes among 25,849 (3.2%) participants without stroke/TIA at baseline, and 310 strokes among 3,101 (10.0%) with stroke/TIA at baseline. In those stroke-free at baseline, there was an age-by-race interaction (p = 0.0003) with a substantially higher risk among blacks than whites at age 45 (HR = 2.69; 95% CI: 1.85 - 3.91), but with increasing age to age 85 this disparity disappeared (HR = 0.95; 95% CI: 0.74 - 1.23). However, there was a constant (p = 0.98) 21% non-significantly higher risk among blacks over the entire age range. For both blacks and whites, the impact of increasing age had a substantially smaller impact on recurrent than incident stroke. The traditional risk factors had a generally smaller impact for recurrent than incident stroke (significantly for atrial fibrillation and heart disease), however, they remained significantly associated with increased risk for recurrent stroke (see table).
Discussion: The role of race and age differed for incident versus recurrent stroke, while the traditional risk factors persisted as indicators of higher risk for recurrent stroke. The smaller impact of stroke risk factors on recurrent stroke should be interpreted with caution, as the higher event rate in this group could imply that the risk factors still have a powerful effect on absolute risk.
Author Disclosures: G. Howard: None. B. Kissela: None. D.O. Kleindorfer: None. M.M. Safford: None. M. Cushman: None. E.Z. Soliman: None. S.E. Judd: None. C.S. Moy: None. D.T. Lackland: None. L.A. McClure: None. V.J. Howard: None.
- © 2014 by American Heart Association, Inc.