Thrombosis and haemostasis
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Patients at high risk for venous thrombosis (VT) following knee arthroscopy could potentially benefit from thromboprophylaxis. We explored the predictive values of environmental, genetic risk factors and levels of coagulation markers to integrate these into a prediction model. Using a population-based case-control study into the aetiology of VT, we developed a Complete (all variables), Screening (easy to use in clinical practice) and Clinical (only environmental risk factors) model. ⋯ Twelve predictor variables (8 environmental, 3 haemorheological and 1 genetic) were selected from 52 candidates and incorporated into the Complete model (area under the curve [AUC] of 0.81, 95% confidence interval [CI], 0.76-0.86). The Screening model (9 predictors: environmental factors plus factor VIII activity) reached an AUC of 0.76 (95% CI, 0.64-0.88) and the Clinical (and corresponding L-TRiP(ascopy)) model an AUC of 0.72 (95% CI, 0.60-0.83). In the internal and external validation, the Complete model reached an AUC of 0.78 (95% CI, 0.52-0.98) and 0.75 (95% CI, 0.42-1.00), respectively, while the other models performed slightly less well.