A novel dynamic risk score to predict venous thromboembolism (VTE) recurrences after 3 months of anticoagulation in patients with incident VTE and without active cancer

Abstract Background Predicting the risk of recurrent venous thromboembolism (rVTE) during and following anticoagulation is complex. Current models lack the ability to adapt to changing patient conditions over time and fail to account for the direct impact of anticoagulation in real-world clinical settings. Purpose To develop a dynamic risk prediction model for rVTE to help clinicians decide on the duration of anticoagulant therapy in conjunction with a model for bleeding (also submitted to the conference). Methods UK Clinical Practice Research Datalink data (2001-2020) was used to generate a retrospective cohort with first VTE who had received 3 months of anticoagulation. Patient episodes of rVTE were evaluated. Covariates were collected at baseline and subsequently as time-varying data to capture changes post-VTE. Hazards with 95% confidence intervals (CI) were estimated and covariates included in a Fine & Gray model used as predictors of rVTE. An additive (logarithmic) scoring scheme was developed from subdistribution hazard ratios, discrimination (expressed by the C-statistic) estimated from 10-fold cross-validation. Results 51,465 patients with a first VTE were included; 4041 rVTE were identified in 200,698 person-years of observation. Incidence rates for rVTE were 2.01 per 100 person-years. Nineteen independent predictors of rVTE (recorded before or after the VTE diagnosis) were included in the model, 13 associated with increased risk and 6 with decreased risk, Table 1. Patients recognised as lower-risk, medium and higher-risk (10.5%, 37% and 52.5% of the population, respectively, at 90 days after first VTE, assuming no anticoagulation treatment) had an annualised rVTE incidence rate of 2.20, 3.84, and 7.44 per 100 person-years. The C-statistic for rVTE was 0.65 (95%CI, 0.64-0.66). The points scored can be added or subtracted to predict risk (Table 2). Conclusions Our dynamic risk score effectively identifies patients at risk of rVTE three months post their initial VTE diagnosis. It allows for continuous monitoring of risk, and modelling of treatment impact, providing clinicians with a pragmatic tool to help determine treatment duration, and adapt their strategies in response to evolving patient conditions.Table 1:Predictors for VTE recurrenceTable 2:VTE recurrence risk score