Perioperative Anemia: Is It Still an Innocent Bystander?

In multiple clinical settings, anemia has been associated with increased risk for poor outcomes such as lower health-related quality of life, more frequent hospitalizations and higher mortality.^1-3  The World Health Organization defines anemia as a hemoglobin value <12 g/dL in women and <13 g/dL in men.⁴  These definitions of anemia are clinically relevant, as data from the Network of Ontario Transfusion Coordinators (ONTraC) has demonstrated an increased rate of transfusion at preoperative hemoglobin values below 13 g/dL⁵ , and other retrospective data demonstrate an increase in mortality near these thresholds.^6,7  Treating anemia with red blood cell transfusions also has associated morbidity risk.^8,9  Patients who are admitted to the hospital with normal hemoglobin values and subsequently developed hospital-acquired anemia have an increased risk for in-hospital mortality.^10,11 Hence, anemia should not be considered an innocent bystander,¹² but...