Estimated glomerular filtration rate, anemia and outcomes in patients with ischemic stroke

Background: Anemia is highly prevalent in patients with low estimated glomerular filtration rate (eGFR). However, the combined effect of anemia and low eGFR on the prognosis of stroke has not been well studied. Methods: Data of patients with acute ischemic stroke in the prospective cohort study of China National Stroke Registry was reviewed. According to the levels of eGFR and hemoglobin, patients were categorized into four groups: low eGFR (<60 mL/min per 1.73 m(2)) or normal eGFR (>= 60 mL/min per 1.73 m(2)) with or without anemia. Multivariate logistic regression methods were used to analyze the association between eGFR with or without anemia and outcomes after stroke [the poor functional outcome (modified Rankin Scale, mRS 3-6), mortality and stroke recurrence] at 3 months and 1 year. Results: This study included 8,303 stroke patients. After adjusting for the confounding factors, low eGFR with normal hemoglobin increased the risk of mortality at 1 year of follow-up [odds ratio (OR) =1.50; 95% confidence interval (95% CI), 1.14-1.97]. Anemia with normal eGFR was not associated with any poor outcome at 1-year of follow-up. In patients with both low eGFR and anemia, there was an increased risk of 1-year poor functional outcome (OR 1.73; 95% CI, 1.30-2.29), mortality (OR 2.64; 95% CI, 1.94-3.59) and stroke recurrence (OR 1.42; 95% CI, 1.06-1.91). Combined and interactive effects of the pattern of low eGFR and anemia on the poor functional outcome (P for interaction =0.02) and all-cause mortality (P for interaction =0.046) were observed. Conclusions: Ischemic stroke patients with concurrent low eGFR and anemia increased risks of poor functional outcome, mortality and stroke recurrence after 1-year follow-up.