Predicting disease recurrence in patients with previous unprovoked venous thromboembolism: a proposed prediction score (DASH)

Summary.  Background:  In patients with unprovoked venous thromboembolism (VTE), the optimal duration of anticoagulation is anchored on estimating the risk of disease recurrence. Objectives:  We aimed to develop a score that could predict the recurrence risk following a first episode of unprovoked VTE, pooling individual patient data from seven prospective studies. Methods:  One thousand eight hundred and eighteen cases with unprovoked VTE treated for at least 3 months with a vitamin K antagonist were available for analysis. Optimism‐corrected Cox regression coefficients were used to develop a recurrence score that was subsequently internally validated by bootstrap analysis. Results:  Abnormal D‐dimer after stopping anticoagulation, age < 50 years, male sex and VTE not associated with hormonal therapy (in women) were the main predictors of recurrence and were used to derive a prognostic recurrence score (DASH, D‐dimer, Age, Sex, Hormonal therapy) showing a satisfactory predictive capability (ROC area = 0.71). The annualized recurrence risk was 3.1% (95% confidence interval [CI], 2.3–3.9) for a score ≤ 1, 6.4% (95% CI, 4.8–7.9) for a score = 2 and 12.3% (95% CI, 9.9–14.7) for a score ≥ 3. By considering at low recurrence risk those patients with a score ≤ 1, life‐long anticoagulation might be avoided in about half of patients with unprovoked VTE. Conclusions:  The DASH prediction rule appears to predict recurrence risk in patients with a first unprovoked VTE and may be useful to decide whether anticoagulant therapy should be continued indefinitely or stopped after an initial treatment period of at least 3 months.