ABSTRACT
BACKGROUND: Guidelines suggest indefinite anticoagulation after unprovoked venous thromboembolism (VTE) unless the bleeding risk is high, yet there is no consistent guidance on assessing bleeding risk. This study aimed to evaluate the performance of five bleeding risk tools (RIETE, VTE-BLEED, CHAP, VTE-PREDICT, and ABC-bleeding). METHODS: PLATO-VTE, a prospective cohort study, included patients aged ≥40 years with a first unprovoked VTE. Risk estimates were calculated at VTE diagnosis and after 3 months of treatment. Primary outcome was clinically relevant bleeding, as per ISTH criteria, during 24-month follow-up. Discrimination was assessed by the area under the receiver operating characteristic curve (AUROC). Patients were classified as having a 'high-risk' and 'non-high-risk' of bleeding according to predefined thresholds; bleeding risk in both groups was compared by hazard ratios. RESULTS: Of 514 patients, 38 (7.4%) had an on-treatment bleeding. AUROCs were 0.58 (95%CI, 0.48-0.68) for ABC-bleeding, 0.56 (95%CI, 0.46-0.66) for RIETE, 0.53 (95%CI, 0.43-0.64) for CHAP, 0.50 (95%CI, 0.41-0.59) for VTE-BLEED, and 0.50 (95%CI, 0.40-0.60) for VTE-PREDICT. The proportion of high-risk patients ranged from 1.4% with RIETE to 36.9% with VTE-BLEED. The bleeding incidence in the high-risk groups ranged from 0% with RIETE to 13.0% with ABC-bleeding, and in the non-high-risk groups from 7.7% with ABC-bleeding to 9.6% with RIETE. Hazard ratios ranged from 0.93 (95%CI, 0.46-1.9) for VTE-BLEED to 1.67 (95%CI, 0.86-3.2) for ABC-bleeding. Recalibration at 3-month follow-up did not alter the results. CONCLUSIONS: In this cohort, discrimination of currently available bleeding risk tools was poor. These data do not support their use in patients with unprovoked VTE.
