Role of Anemia in Traumatic Brain Injury

Background: Few studies have investigated the effects of anemia in patients with traumatic brain injury (TBI). The objective of this study was to examine the role of anemia and blood transfusion on outcomes in TBI patients. Study Design: We performed a retrospective review of all blunt trauma patients with TBI admitted to the ICU from July 1998 to December 2005. Admission and daily ICU blood hemoglobin (hemoglobin) levels and blood transfusions during the first week of hospitalization were measured. Anemia was defined as a hemoglobin < 9 g/dL occurring on 3 consecutive blood draws. The role of anemia and blood transfusion was investigated using logistic regression adjusting for factors, with p < 0.2 from the bivariate analysis. Results: During the study period, 1,150 TBI patients were admitted to the ICU. When both anemia and blood transfusion were included in the full model, blood transfusion was significantly associated with higher mortality (adjusted odds ratio [AOR], 2.19 [95% CI, 1.27, 3.75]; p = 0.0044) and more complications (AOR, 3.67 [95% CI, 2.18, 6.17]; p < 0.0001), but anemia was not. But when transfusion was not included in the full model, anemia was a significant risk factor for mortality (AOR, 1.59 (95% CI, 1.13, 2.24); p = 0.007) and for complications (AOR, 1.95 [95% CI, 1.42, 2.70]; p < 0.0001). Conclusions: Blood transfusion is associated with significantly worse outcomes in traumatic brain injured patients. In addition, blood transfusion is a major contributing factor to worse outcomes in TBI patients who are anemic. We caution against the liberal use of blood in TBI patients.