Abstract 2877: The Impact of Anemia on Mortality in Patients with Coronary Artery Disease: Results from the Coronary Artery Surgery Study
Introduction: Anemia may predict long-term mortality in patients with coronary artery disease (CAD) and is closely associated with chronic kidney disease (CKD). Erythropoietin therapy may alter the association of anemia with cardiovascular outcomes and is associated with increased mortality when the hemoglobin is normalized. Therefore, we sought to determine the interaction of anemia and CKD as risk factors for mortality in patients with CAD before the availability of recombinant erythropoietin in the Coronary Artery Surgery Study (CASS).
Methods and Results: We analyzed 14,574 patients with CAD from the CASS registry for whom creatinine and hematocrit were available. Anemia was defined as a hematocrit <39% in males and < 36% in females as per the WHO definition and renal function was estimated using the Cockroft-Gault formula. Patients with anemia had a significantly higher all cause-mortality at 5 years (19 vs. 12%), at 10 years (33 vs. 24%), and at 15 years (46 vs. 44%) (p < 0.001). After adjusting for significant variables in the univariate analysis including glomerular filtration rate, hematocrit remained a significant predictor of mortality (hazard ratio 1.17; CI 1.09–1.26) (p < 0.0001). However, the interaction term between anemia and renal function was not significant. We also noted a ‘U’ shaped relationship between anemia and mortality (figure⇓).
Conclusions: Anemia is a potentially modifiable independent predictor of mortality in patients with CAD. The relationship between hematocrit and mortality is not linear and higher hematocrits are associated with greater mortality even in the absence of erythropoietin therapy.