Background: We have evaluated whether anemia at admission is associated with ischemic stroke recurrence and composite outcome events (stroke, myocardial infarction, and vascular death) according to the age, presence of cerebral artery stenosis, stroke subtype, and initial severity of stroke.
Methods: All 27145 patients with transient ischemia attack or acute ischemic stroke admitted between April 2008 and November 2014 from the stroke registry of the fifth section of the Clinical Research Center for Stroke (CRCS-5) were selected. The association between anemia and 1-year stroke recurrence, composite outcome events according to age, presence of cerebral artery stenosis, stroke mechanism, and initial severity of stroke were evaluated.
Results: The cumulative 1-year stroke recurrence rate, composite outcome events were significantly higher in patients with anemia than without anemia ( 7.2% vs. 4.8%, p<0.01 for stroke recurrence, 11.8% vs.7.3%, p<0.01 for composite event). Anemia was still an independent predictor of 1-year stroke recurrence and composite vascular event after adjustment (adjusted HR 1.35, 95% CI 1.09-1.66, p<0.01 for stroke recurrence, adjusted HR 1.21, 95% CI 1.03-1.43, p=0.03 for composite outcome events). Anemia significantly increase the stroke recurrence risk in patients with mild to moderate neurological deficit (NIHSS <16, p for interaction=0.04), with stroke of other determined etiology (p for interaction=0.06). Anemia substantially increase the risk of composite outcome events in patients with mild to moderate stroke severity (NIHSS <16, HR 1.84, 95% CI 1.53-2.21, p for interaction<0.01), without cerebral artery stenosis ≥50% (HR 2.02, 95% CI 1.57-2.59, p for interaction=0.03), with stroke of small vessel occlusion (HR 2.74, 95% CI 1.34-5.63, p for interaction=0.09), and with stroke of other determined etiology (HR 2.95, 95% CI 1.69-5.14, p for interaction=0.02).
Conclusion: Anemia is an independent predictor of 1-year ischemic stroke recurrence, composite outcome events of stroke, myocardial infarction, and vascular death. Our data suggests that more attention should be paid to the anemic patients with mild to moderate neurological deficit, small vessel occlusion subtype, and stroke of other determined etiology.