Validation of the HAS-BLED scale for the assessment of bleeding risk in patients on anticoagulation therapy with a diagnosis of venous thromboembolic disease

Abstract

Background: Several models have been developed to assess bleeding risk in patients with venous thromboembolism, such as HAS-BLED, but their external validity has not been adequately assessed. Objective: The objective of the study was to evaluate the discriminative ability and calibration of the HAS-BLED scale for predicting 1-month bleeding risk in patient’s anticoagulated for venous thromboembolism. Materials and Methods: External validation study of a prediction model based on a retrospective cohort of patients with venous thromboembolism treated between November 2019 and January 2022. Calibration of the HAS-BLED scale was evaluated using the Hosmer–Lemeshow test and the ratio of observed to expect events within each risk category. Discriminatory ability was assessed using the area under the curve (AUC) of a receiver operating characteristic curve. Results: We included 735 patients (median age 64 years, female sex 55.2%), pulmonary embolism was diagnosed in most patients (60.7%), and 4.9% presented bleeding events. Regarding calibration, the HAS-BLED scale systematically underestimates the risk both in the general population (ROE 3.76, p < 0.001) and in cancer patients (ROE 4.16). The Hosmer–Lemeshow test rejected the hypothesis of adequate calibration (p < 0.001). Discriminatory ability was limited both in the general population (AUC = 0.57, 95% confidence interval [CI]: 0.48-0.66) and in the subgroup with active cancer (AUC = 0.53, 95% CI: 0.36-0.69). Conclusion: The HAS-BLED scale in patients with venous thromboembolism underestimates the risk of bleeding at 1 month and has a low ability to discriminate high-risk patients. Cautious interpretation of the scale is recommended until additional evidence is available.

Keywords

• Anticoagulation. Bleeding risk. Prediction models. Venous thromboembolism.