Preoperative antithrombotic therapy and risk of blood transfusion and mortality following hip fracture surgery: a Danish nationwide cohort study

Hip fracture surgery is associated with high risk of bleeding and mortality. The patients often have cardiovascular comorbidity, which requires antithrombotic treatment. This study found that preoperative use of oral anticoagulants was not associated with transfusion or mortality following hip fracture surgery, whereas increased risk may exist for antiplatelet drugs.Hip fracture surgery is associated with high bleeding risk and mortality; however, data on operative outcomes of hip fracture patients admitted while on antithrombotic therapy is sparse. We examined if preoperative antithrombotic treatment was associated with increased use of blood transfusion and 30-day mortality following hip fracture surgery.Using data from the Danish Multidisciplinary Hip Fracture Registry, we identified 74,791 hip fracture surgery patients aged ≥ 65 years during 2005-2016. Exposure was treatment with non-vitamin K antagonist oral anticoagulant (NOAC), vitamin K antagonists (VKA), or antiplatelet drugs at admission for hip fracture. Outcome was blood transfusion within 7 days postsurgery and death within 30 days.A 45.3% of patients received blood transfusion and 10.6% died. Current NOAC use was associated with slightly increased risk of transfusion (adjusted relative risk (aRR) 1.07, 95% confidence interval (CI) 1.01-1.14), but similar mortality risk (adjusted hazard ratio (aHR) 0.88, 95% CI 0.75-1.03) compared with non-users. The pattern remained when restricting to patients with short surgical delay (< 24 h). VKA users did not have increased risk of transfusion or mortality. The risks of transfusion (aRR 1.15 95% CI 1.12-1.18) and 30-day mortality (aHR 1.18 95% CI 1.14-1.23) were increased among antiplatelet users compared with non-users.In an observational setting, neither preoperative NOAC nor VKA treatments were associated with increased risk of 30-day postoperative mortality among hip fracture patients. NOAC was associated with slightly increased risk of transfusion. Preoperative use of antiplatelet drugs was associated with increased risk of transfusion and mortality.