Abstract 17765: Mild Preoperative Anemia is an Independent Predictor of Mortality and Cardiovascular Events in Patients Undergoing Elective Major Noncardiac Surgery

Abstract

Background: Preoperative anemia has been recognized as an important risk factor for perioperative red blood cell transfusions and adverse events in patients undergoing noncardiac surgery. Mild anemia has not unequivocally shown to be a risk factor for death, unless cardiac disease is present or major blood loss occurs. Objective: To evaluate the prevalence of preoperative anemia and its effect on 30-day postoperative outcome in subjects undergoing elective major noncardiac surgery. Methods: A retrospective cohort study was performed in 1630 patients, 40 years and older, who underwent major noncardiac surgery.Based on preoperative hemoglobin levels and gender, we stratified patients into the next categories of anemia: mild (11-12 g/dl), moderate (10-11 g/dl) and severe (<10 g/dl) for female; mild (12-13 g/dl), moderate (11-12 g/dl) and severe (<11 g/dl) for male. Age, risk factors, previous chronic heart or lung disease, renal function and concomitant treatment were used in a binary logistic regression to determine the impact of anemia in prognosis. The primary outcome measure was a composite of 30-day postoperative mortality or cardiovascular events (cardiac arrest, myocardial infarction, stroke or pulmonary embolism). Results: The overall prevalence of anemia was 18.8%. Thirty-day mortality and cardiac event rate increased with the presence of anemia (table). Mild, moderate and severe anemia were associated with a two-fold (OR 2.07; CI 95%: 1.04-4.11), three-fold (OR 2.93; CI 95%: 1.45-5.94) and four-fold (OR 4.09; CI 95%:1.87-8.95) increases in the risk of MACCE respectively. Conclusions: Anemia is a prevalent risk factor in patients undergoing major noncardiac surgery. Even mild degrees of preoperative anemia are associated with an increased risk of 30-day postoperative mortality and cardiovascular events. Further studies are needed in order to evaluate whether treatment of preoperative anemia could reduce postoperative mortality.