The HERDOO2 Score Predicts Recurrent VTE in Women

As many as 10% of patients with unprovoked venous thromboembolism (VTE) develop recurrent VTE within 1 year after stopping anticoagulation therapy. To identify a subgroup of patients with unprovoked VTE who were at low risk for recurrence, researchers previously derived the HERDOO2 rule (Hyperpigmentation, Edema, or Redness in either leg; d-dimer level ≥250 µg/L; Obesity [body-mass index ≥30 kg/m²]; and Older [age, ≥65]). In the original derivation study, women with ≤1 HERDOO2 criterion had a low recurrence rate (1.6% annually), but the rule was unable to identify a low-risk male group (NEJM JW Gen Med Oct 1 2008 and CMAJ 2008; 179:417).

Now, the researchers have validated this rule prospectively in 2785 patients with unprovoked VTE who had …