Anemia Increases All-Cause Mortality Risk in Stroke Survivors on Antiplatelet Therapy: A Retrospective Cohort Study

Introduction: Approximately 20% of patients with stroke are anemic, and previous studies have identified a U-shaped relationship between hemoglobin levels and all-cause mortality in stroke survivors. However, these studies have not specifically focused on patients with stroke taking antiplatelet agents. This study investigates the impact of anemia and hemoglobin (HGB) on mortality in this population. Methods: This study included 356 stroke survivors from the National Health and Nutrition Examination Survey 1999-2018 who were taking antiplatelet agents. It analyzed the impact of HGB levels and anemia on all-cause mortality using Cox regression, examined the nonlinear relationship between HGB and mortality through restricted cubic splines (RCS), and illustrated survival over time using Kaplan-Meier survival curves. Results: RCS analysis revealed no nonlinear relationship between HGB and all-cause mortality (P for overall < 0.01, P for nonlinear = 0.36), with lower HGB levels associated with an increased risk of all-cause mortality. Cox regression analysis showed that HGB was negatively associated with mortality risk across all models (Model 4: hazard ratio = 0.81, 95% confidence intervals 0.73-0.91, P < 0.01). Additionally, anemia significantly increased the risk of mortality in all models (Model 4: hazard ratio = 2.05, 95% confidence intervals 1.43-2.95, P < 0.01). Kaplan-Meier survival curves demonstrated that the survival rate in the anemic group was significantly lower than that of the non-anemic group (P < 0.01). Conclusion: In stroke survivors taking antiplatelet agents, anemia is associated with an increased risk of all-cause mortality, while HGB levels are negatively correlated with mortality risk.