Thrombotic and Infectious Morbidity Are Associated with Transfusion in Posterior Spine Fusion

Background: Although previous investigators have established an association between blood transfusion and adverse outcomes, the relative frequency of different morbid events and the association with transfusion dose are not well understood. Questions/Purposes: The purpose of the study is to characterize the relationship between blood transfusion and different types of morbidity after posterior spine fusion. Methods: We retrospectively analyzed electronic medical records for 963 patients who underwent posterior spinal fusion surgery at a single institution, of which 603 (62.6%) received an allogeneic blood transfusion. Then, we assessed patient and surgical characteristics in a risk-adjusted fashion to identify various morbid event rates and independent predictors in these adverse outcomes. Results: Compared to the non-transfused patients, transfused patients had a higher incidence of any morbid event (9.1 vs. 2.5%. P < 0.0001), thrombotic events (4.6 vs. 1.1%, P = 0.0025), and hospital-acquired infections (2.3 vs. 0.6%, P = 0.039). Renal, respiratory, and ischemic morbidity occurred less frequently and were not more common in transfused patients. Risk-adjusted analysis revealed a dose-response effect, whereby for each unit of allogeneic blood transfused, the risks of any morbid event (OR 1.183; 95% CI 1.103–1.274; P < 0.0001), thrombotic complication (OR 1.104; 95% CI 1.032–1.194; P = 0.0035), and infectious complication (OR 1.182; 95% CI 1.077–1.332; P = 0.0002) were increased. Conclusion: Our data demonstrate risk-adjusted and transfusion dose-related increases in perioperative morbidity, with thrombotic and infectious events being the most common.