Association between venous thromboembolism and perioperative allogeneic transfusion.

HYPOTHESIS: Perioperative allogeneic blood product transfusion would be associated with venous thromboembolic complications in surgical patients.
DESIGN: Observational study using a state discharge database.
SETTING: Nonfederal acute care hospitals in Maryland performing colorectal cancer resections between January 1, 1994, and December 31, 2000. PATIENTS: We obtained data on 14 014 adult patients having a primary diagnosis code for colorectal cancer and a primary procedure code for colorectal resection. MAIN OUTCOME MEASURES: The primary outcome variable was a discharge diagnosis of venous thromboembolism (VTE).
RESULTS: Venous thromboembolism occurred in 1% of patients and was associated with an adjusted 3.8-fold increase in mortality (odds ratio, 3.8; 95% confidence interval, 2.1-6.8), a 61% increase in mean hospital length of stay, and a 72% increase in mean total hospital charges. Risk factors for VTE after adjustment included transfusion, female sex, age 80 years or older, moderate to severe liver disease vs no liver disease, admission through the emergency department, and low annual surgeon case volume. Transfusion was associated with an increase in the odds of developing VTE in women (odds ratio, 1.8; 95% confidence interval, 1.2-2.6) but not in men (odds ratio, 0.9; 95% confidence interval, 0.5-1.9). In the absence of transfusion, female compared with male sex was not associated with an increased risk of VTE (odds ratio, 1.2; 95% confidence interval, 0.8-1.7).
CONCLUSIONS: In this large observational study of patients undergoing colorectal cancer resection, perioperative allogeneic blood transfusion was associated with an increased risk of VTE in women but not in men. Given the substantial morbidity and mortality associated with VTE and the implication that this finding has for postoperative management in women, this association must be confirmed in independent studies.