Greater Stroke Severity Predominates over All Other Factors for the Worse Outcome of Cardioembolic Stroke

Abstract

Background: Cardioembolic (CE) strokes are more disabling and more fatal than non-CE strokes. Multiple prognostic factors have been recognized, but the magnitude of their relative contributions has not been well explored. Methods: Using a prospective stroke outcome database, we compared the 3-month outcomes of CE and non-CE strokes. We assessed the relative contribution of each prognostic factor of initial stroke severity, poststroke complications, and baseline characteristics with multivariable analyses and model fitness improvement using -2 log-likelihood and Nagelkerke R-2. Results: This study included 1233 patients with acute ischemic stroke: 193 CE strokes and 1040 non-CE strokes. Compared with the non-CE group, CE group had less modified Rankin Scale (mRS) 0-2 outcomes (47.2% versus 68.5%; odds ratio [95% confidence interval], .41 [.30-.56]), less mRS 0-1 outcomes (33.7% versus 53.5%; .44 [.32-.61]), more mRS 5-6 outcomes (32.1% versus 10.9%; 3.88 [2.71-5.56]), and higher mortality (19.2% versus 5.2%; 4.33 [2.76-6.80]) at 3 months. When adjusting either baseline characteristics or poststroke complications, the outcome differences between the 2 groups remained significant. However, adjusting initial National Institute of Health Stroke Scale (NIHSS) score alone abolished all outcome differences except for mortality. For mRS 0-2 outcomes, the decrement of -2 log-likelihood and the Nagelkerke R-2 of the model adjusting initial NIHSS score alone approached 70.2% and 76.7% of the fully adjusting model. Conclusion: Greater stroke severity predominates over all other factors for the worse outcome of CE stroke. Primary prevention and more efficient acute therapy for stroke victims should be given top priorities to reduce the burden of CE strokes.