Intra-operative blood transfusion in elderly patients on antithrombotic therapy

Background: Many elderly patients are receiving antithrombotics, which may increase intra-operative blood loss. We aimed to assess whether chronic antithrombotic therapy was associated with intra-operative transfusion of packed red blood cells in patients at least 80 years of age undergoing elective procedures. Methods: We performed a secondary analysis of the prospective, observational European multicentre study entitled POSE (peri-interventional outcome study in the elderly) including 9497 surgical patients aged 80 years and older in 177 centres from October 2017 to December 2018. In this secondary analysis we included POSE patients who underwent elective procedures and with available data on chronic antithrombotic therapy. The primary outcome was intra-operative transfusion of packed red blood cells and results were analysed using multiple logistic regression model. We adjusted for the following predetermined explanatory variables: Age, sex, body mass index, American Society of Anaesthesiologists Physical Status Classification System, baseline haemoglobin concentration, disseminated cancer, and type and severity of surgery. Results: A total of 7174 patients were included of whom 4073 (56.8%) were on antithrombotic therapy. Among patients on antithrombotic therapy 191 (4.7%) received intra-operative blood transfusion compared with 98 (3.2%) of patients not on chronic antithrombotic therapy (crude odds ratio: 1.51, 95% CI 1.18–1.94). Following multiple logistic regression analysis, the adjusted odds ratio was 0.98; 0.73–1.32. We found that chronic antithrombotic therapy was associated with intra-operative transfusion of packed red blood cells in elderly patients undergoing elective procedures in an unadjusted analysis, but not in a multivariate adjusted model.