Predicting Bleeding Risk on Anticoagulant Therapy for Venous Thromboembolism

Development and Validation of Clinical Prediction Rules for Bleeding for Patients on Anticoagulant Therapy for Venous Thromboembolism

The main objective of the study is to develop or validate a clinical prediction rule for major bleeding in patients on oral anticoagulant therapy who have been safely anticoagulated without bleeding or venous thromboembolism (VTE) recurrence for at least 3 months since diagnosis and are being considered for long-term oral anticoagulant therapy.

Study Overview

• Status: Completed
• Conditions: Venous Thromboembolism

Detailed Description

Oral anticoagulant therapy for patients who are at risk of developing blood clotting problems is used by between 400,000-600,000 Canadians annually. The use of this drug represents the most common cause of patient adverse medical outcomes due to medical errors. Furthermore, many patients have adverse outcomes using these drugs because physicians are not able to predict which patients are likely to have bleeding outcomes. Much effort has gone into developing ways to predict which patients are at risk of clotting but almost no work has gone into ways of predicting which patients would be at high risk of bleeding. This information is required to balance off the risk-benefits and to enable physicians and patients to understand the risks and benefits of taking these medications. Our study will develop a tool that can be used to predict bleeding risk in patients taking oral anticoagulant therapy. It will enable more informed decision making by both physicians and patients and will result in better control of the use of these drugs. In addition, patients who are at risk for being difficult to accurately dose on oral anticoagulants will be identified through our study.

• Study Type: Observational
• Enrollment (Actual): 2537

Contacts and Locations

Study Locations

• Canada
  • Nova Scotia
    • Halifax, Nova Scotia, Canada, B3H 1V7
      • Queen Elizabeth II Health Sciences Centre
  • Ontario
    • Hamilton, Ontario, Canada, L8L 2X2
      • Hamilton General Hospital
    • Hamilton, Ontario, Canada, L8V 1C3
      • Hamilton Health Sciences
    • London, Ontario, Canada, N6A 4G5
      • London Health Sciences Centre
    • Ottawa, Ontario, Canada, K1H 8L6
      • Ottawa Hospital Research Institute
  • Quebec
    • Montreal, Quebec, Canada, H3G 1A4
      • Montreal General Hospital
    • Montreal, Quebec, Canada, H4J 1C5
      • Hopital Du Sacre Coeur de Montreal
    • Montreal, Quebec, Canada, H3T 1E2
      • Sir Mortimer B Davis Jewish General Hospital
    • Montreal, Quebec, Canada, H3T 1M5
      • St. Mary's Hospital Centre
• United Kingdom
  • Oxford, United Kingdom, 0X3 7LJ
    • Oxford Haemophilia and Thrombosis Centre, Churchill Hospital
• United States
  • Massachusetts
    • Burlington, Massachusetts, United States, MA01805
      • Lahey Clinic
  • Michigan
    • Detroit, Michigan, United States, 48202
      • Henry Ford Health System

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Outpatients being treated for venous thromboembolism

Description

Inclusion Criteria:

• >=18 years old
• provoked or unprovoked venous thromboembolism
• objectively confirmed venous thromboembolism
• treated with an oral anticoagulant(vitamin K antagonist or new oral anticoagulant) for at least 3 months with plans to continue long-term
• if taking a vitamin K antagonist; INR target is between 2.0-3.0
• if taking a vitamin K antagonist; must have taken it for the last 3 consecutive weeks (minimum)

Exclusion Criteria:

• major bleeding while taking oral anticoagulants
• active bleeding at study enrollment
• active cancer - current or at the time of VTE diagnosis
• unable to provide written informed consent
• refusal to provide written informed consent

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Major bleeding (International Society on Thrombosis and Haemostasis(ISTH) criteria)	ongoing for 3-7 years with follow-up phone calls at 6-month intervals

Secondary Outcome Measures

Outcome Measure	Time Frame
Clinically relevant non-major bleeding (International Society on Thrombosis and Haemostasis(ISTH) criteria)	ongoing for 3-7 years with follow-up phone calls at 6-month intervals
recurrent venous thromboembolism	ongoing for 3-7 years with follow-up phone calls at 6-month intervals
death (all causes)	ongoing for 3-7 years with follow-up phone calls at 6-month intervals

Collaborators and Investigators

• Sponsor: Ottawa Hospital Research Institute
• Collaborators: Canadian Institutes of Health Research (CIHR); Heart and Stroke Foundation of Ontario
• Investigators: Principal Investigator: Phil S Wells, MD, MSc, Ottawa Hospital Research Institute

Study record dates

Study Major Dates

• Study Start: September 1, 2008
• Primary Completion (Actual): September 1, 2016
• Study Completion (Actual): October 1, 2016

Study Registration Dates

• First Submitted: November 10, 2008
• First Submitted That Met QC Criteria: November 10, 2008
• First Posted (Estimate): November 11, 2008

Study Record Updates

• Last Update Posted (Estimate): October 27, 2016
• Last Update Submitted That Met QC Criteria: October 25, 2016
• Last Verified: October 1, 2016

More Information

Terms related to this study

• Keywords: predictors; warfarin; venous thromboembolism; deep vein thrombosis; pulmonary embolism; bleeding risk; side effect; vitamin k antagonist; clinical prediction rule; long-term oral anticoagulant therapy
• Additional Relevant MeSH Terms: Pathologic Processes; Cardiovascular Diseases; Vascular Diseases; Embolism and Thrombosis; Hemorrhage; Thromboembolism; Venous Thromboembolism
• Other Study ID Numbers: OHREB 2008270-01H; MOP130388 (Other Identifier: Canadian Institutes of Health Research (CIHR))

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED