ANEMIA AND ELEVATED HEMOGLOBIN IN STROKE PATIENTS TREATED WITH THROMBECTOMY - a Cohort study from the EVATRISP Collaboration

Background: Anemia and elevated hemoglobin levels (HL) are frequent in ischemic stroke patients and their prognostic meaning is unclear. Therefore, we aimed to study the effect of HL on functional outcome and risk of symptomatic intracerebral hemorrhage (sICH) in stroke patients treated with thrombectomy. Methods: In this prospective multicenter study from the EndoVAscular Treatment and ThRombolysis for Ischemic Stroke Patients Registry (EVA-TRISP), we investigated whether HL were associated with 3-month poor outcome (mRS 3-6), mortality, and sICH. HL were categorized as anemia (<120g/L; moderate/severe anemia <100g/L), normal HL (female:120-155g/L, male:120-170g/L) and elevated HL (female:>155g/L; male:>170g/L). Unadjusted and adjusted odds ratios with 95% confidence intervals (OR [95%-CI]) from logistic regression models were calculated. Additionally, we calculated fitted conditional mean outcomes on HL as a continuous variable. Results: Among 9,967 EVT-treated patients, 7,168 (71.9%) had normal HL, 2,496 (25.1%) had anemia, including 618 (6.2%) with moderate/severe anemia, and 303 (3%) had elevated hemoglobin. Anemia vs. normal HL was independently associated with poor outcome (ORadjusted 1.48[1.32-1.66]) and mortality (ORadjusted 1.69[1.50-1.90]). Moderate/severe anemia had the highest odds for poor outcome (ORadjusted 1.75[1.41-2.18]) and mortality (ORadjusted 2.80[2.28-3.43]). Elevated hemoglobin vs. normal HL was independently associated with poor outcome (ORadjusted 1.33[1.01-1.74]) and mortality (ORadjusted 1.49[1.09-2.03]). HL were not associated with occurrence of sICH. HL as continuous variable showed a U-shaped relationship for mortality and poor outcome. Conclusion: The more severe both the anemia and the hemoglobin level are, the higher the likelihood of poor outcome and death. They may constitute targets for interventions to improve outcomes.