HERDOO2 decision rule for recurrent venous thromboembolism
Clinical decision rule to identify patients at low risk of recurrent venous thromboembolism after 5-7 months of oral anticoagulant therapy.
HERDOO2 stands for: hyperpigmentation, edema, redness, D-dimer, obesity, older age, 2 scores.
Research authors: Marc A Rodger, Susan R Kahn, Philip S Wells, David A Anderson, Isabelle Chagnon, Grégoire Le Gal, Susan Solymoss, Mark Crowther, Arnaud Perrier, Richard White, Linda Vickars, Tim Ramsay, Marisol T. Betancourt, Michael J. Kovacs
Details Formula Study characteristics Files & References
Model author
Model ID
Revision date
MeSH terms
  • Thromboembolism, Venous
  • Anticoagulant Drugs
  • Clinical Prediction Rule
  • Model type
    Linear model (Calculation)
    No Formula defined yet
    Condition Formula

    Additional information

    In 2008, Rodger et al. proposed the HERDOO2 model, deriving data from a Canadian multicenter prospective cohort study that included 646 patients with a first unprovoked VTE event followed up for 18 months after discontinuing oralanticoagulation therapy.

    Study Population

    Total population size: 646
    Males: {{ model.numberOfMales }}
    Females: {{ model.numberOfFemales }}

    Continuous characteristics

    Name Mean SD Unit
    Age 52.5 17.5 years
    Weight 87.5 23.6 kg
    Height 171.6 10.8 cm
    BMI 29.1 7.2 kg/m2
    d-Dimer 307 403 ug/L
    Homocysteine 10.1 8.0 umol/L
    Hemoglobin 142.2 15.0 g/L
    Factor VIII 1.7 0.55 U/mL

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Abnormal baseline compression ultrasound Recurrent VTE 45
    No VTE 186
    Abnormal baseline imaging Recurrent VTE 64
    No VTE 327
    Factor V Leiden Recurrent VTE 19
    no VTE 81
    VTE Recurrent 91
    No VTE 555
    V/Q scan or PVO result <95% Recurrent VTE 38
    No VTE 272
    Post-thrombotic signs HER 215
    Edema 149
    Redness 71
    Hyperpigmentation 93
    History of COPD or emphysema Recurrent VTE 1
    No VTE 39
    Family history of VTE recurrent VTE 18
    no VTE 135
    HERDOO2 decision rule for recurrent venous thromboembolism
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

    Related files

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    Supporting Publications

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    HERDOO2 risk score: points

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    Outcome stratification

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    Conditional information

    Result interpretation

    Interpretation of results:

    • In a study by Rodger et al (2008) including 646 patients with a first unprovoked venous thromboembolism (VTE) event, an annual risk of VTE recurrence of 9.3% [95% confidence interval (CI) 7.7–11.3%) was recorded in the whole cohort, and of 13.7% in men.
    • On the basis of these results, the authors recommend a long-term anticoagulant treatment as always indicated for all men.
    • Women with a total risk score of 0 to 1 had an annual risk of recurrence of 1.6% (95% CI 0.3-4.6%), whereas those who had a score of 2 or more had an annual risk of 14.1% (95% CI 10.9–17.3%) and deserved, according to the authors, an indefinite anticoagulation.

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    Calculations alone should never dictate patient care, and are no substitute for professional judgement. See our full disclaimer.

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