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Risk stratification of recurrent venous thromboembolism in patients with cancer-associated VTE
histology of the malignancy all impact the 6-month rate of recurrent VTE.4-8 The anticoagulant therapy used [e.g. vita- min K antagonist, direct oral anticoagulants or low molec- ular weight heparin (LMWH)] may also influence the rate of recurrent VTE. Reliable identification of which patients are at high or low risk of recurrent VTE recurrence must be performed to aid clinical decision-making regarding the type of anticoagulant therapy.
For this, the Ottawa score was designed to stratify the risk of recurrent VTE during the first six months of antico- agulant therapy in patients with cancer-associated VTE.9 Two scores were derived. The original score (female sex, lung cancer, and prior history of VTE each give 1 point; breast cancer gives a negative point; cancer stage I gives 2 negative points) dichotomizes patients into low (score ≤ 0) or high (score ≥ 1) risk for VTE recurrence. The modified score (female sex, lung cancer, and prior history of VTE each give 1 point; breast cancer and cancer stage I + II each give a negative point) classifies patients into low (score ≤−1), intermediate (score = 0), and high (score ≥ 1) risk for VTE recurrence. However, the accuracy of these two clin-
ical models remains to determine.
To determine if the Ottawa risk score (i.e. original and
modified) can reliably identify the risk of recurrent VTE during the first six months of anticoagulation in cancer patients with VTE, we conducted a systematic review and meta-analysis of the literature.
Methods
The guidelines of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement were followed. The systematic review was registered with the International Prospective Registry of Systematic Reviews (PROSPERO CRD42018099506).
Search strategy and study selection
We systematically searched Medline and Embase, using the following key words: recurrent venous thromboembolism AND cancer AND (decision tree OR clinical prediction rule OR clinical prediction score OR clinical decision rule OR management stud-
Figure 1. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement flow dia- gram.
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