What is the effect of extended anticoagulation with different anticoagulants on recurrence risk reduction and risk of bleeding in individual patients with venous thromboembolism (VTE)?
Estimating individual treatment effects has the potential to identify in which VTE patients the benefits of extended anticoagulation outweigh the risks.
We propose a prognostic study in which prediction models will be derived and validated using pooled individual patient data from existing international landmark studies.
The intended study population consists of patients with VTE whom participated in clinical trials and prospective cohorts with a study follow-up time of >12 months after (dis)continuing anticoagulation, and data available on candidate predictors, treatment duration and relevant outcomes.
Separate prediction models will be derived for recurrent VTE, defined as DVT or PE, and bleeding as a composite of major bleeding and clinically relevant, non-major bleeding (CRNMB) defined according to the International Society on Thrombosis and Haemostasis (ISTH). Secondary outcome measure will be non VTE- or bleeding-related mortality.
Two complementary Fine & Gray Subdistribution Proportional Hazard models will be derived: one for the prediction of 5-year recurrent VTE-risk after cessation of anticoagulation, and one for 5-year bleeding risk during anticoagulation. Selection of predictors will be based on existing risk scores and availability in clinical practice. Both model parts will be validated internally and externally by assessing calibration and discrimination.
Models will be combined in an online calculator at www.U-Prevent.com. Patients and their physicians can use the calculator to estimate an individual’s risk of recurrent VTE or bleeding and treatment effects.