Incidence, risk factors and impact of anemia after elective neurosurgery: A retrospective cohort study.

Objectives: Anemia after surgery is common and is associated with adverse clinical outcomes. Understanding the incidence and risk factors for postoperative anemia is important to reduce anemia-related complications and blood transfusion. There is lack of data regarding postoperative anemia and its contributing factors in neurosurgery. This study evaluates the incidence and risk factors of postoperative anemia, and its impact on clinical outcomes. Methods: This was a single centre, retrospective study of patients who underwent elective neurosurgery over seven months. Data regarding age, gender, body mass index, American Society of Anesthesiologists (ASA) physical status, diagnosis, surgery, preoperative hemoglobin, surgery duration, intraoperative blood loss and red blood cell (RBC) transfusion, dose of tranexamic acid, intraoperative fluid balance, years of surgeon's experience, postoperative hemoglobin, postoperative RBC transfusion, Glasgow Coma Scale (GCS) score at hospital discharge, and duration of postoperative intensive care unit and hospital stay were collected. Logistic regression was used to identify predictors of postoperative anemia. Results: The incidence of postoperative anemia was 11.3% (116/1025). On univariate analysis; age, preoperative hemoglobin, surgery duration, gender, ASA grade, surgery type, and surgeon's experience were associated with postoperative anemia. Lower preoperative hemoglobin (p<0.001) and non-tumor surgery (p<0.001) were predictive of postoperative anemia on multivariate analysis. Postoperative anemia resulted in increased RBC transfusion (p<0.001) and lower GCS score at discharge (p=0.012). Conclusions: Atleast one in ten patients undergoing elective neurosurgery develop postoperative anemia. Lower preoperative hemoglobin and non-tumor surgery predict anemia. Anemia results in increased RBC transfusion and lower discharge GCS score.