Risk Factors for Venous Thromboembolism in the Community

December 5, 2012 updated by: Mayo Clinic

Subtherapeutic Heparin Anticoagulation as a Predictor of Recurrent Venous Thromboembolism: A Population-Based Cohort Study

To evaluate the trends in the incidence of venous thromboembolism, to determine the risk factors for venous thromboembolism in patients with medical and surgical illness, and to evaluate the efficacy of the anticoagulant therapy in reducing venous thromboembolism.

Study Overview

Status

Completed

Detailed Description

BACKGROUND:

Venous thromboembolism (VTE) occurs frequently among patients hospitalized for major surgery or hospitalized for a medical illness primarily due to prolonged duration of immobilization. However, many patients undergo major surgery without any occurrence of VTE. Standard prophylactic therapy after surgery is heparin, which reduces the risk of VTE. However, heparin is associated with bleeding complications. Thus, it would be desirable to identify patients at high risk for VTE who might benefit the most from heparin therapy. An important focus of the study is to look at genetic factors which might play an important role in VTE incidence.

DESIGN NARRATIVE:

The study is a population based, retrospective case and case-control investigation of the genetic and environmental determinants of venous thromboembolism in the Rochester Minnesota Olmsted County population. The first five years of the study had three specific aims. The first specific aim was to update the 1966-1995 inception cohort to include Olmsted County residents with VTE during the five year period, 1996-2000. The second aim was to extend the analysis of risk factors for VTE by identifying two Olmsted County residents (controls) without VTE matched by age and gender to each definite or probable case within the 1996-2000 cohort, and to obtain plasma and genomic DNA from all cases and controls and perform a case-control study. The third specific aim was to evaluate the efficacy of anticoagulant therapy to prevent VTE recurrence.

The study was extended through March, 2009 to investigate trends in the incidence of venous thromboembolism, new risk factors including lipid-lowering, beta-blocker, and ACE-inhibitor therapies, and introduction of low molecular weight heparin (LMWH) therapy.

Study Type

Observational

Enrollment (Actual)

385

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Minnesota
      • Rochester, Minnesota, United States, 55905
        • Mayo Clinic

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Using the data resouces of the Rochester Epidemiology Project, we will update the 1966-1995 inception cohort to include Olmsted County, Minnesota residents with with a first-lifetime deep vein thrombosis (DVT) or pulmonary embolism (PE) during the five year period, 1996-2000. All subjects will be followed forward in time through their linked medical records in the community (retrospective cohort study), until death or the most recent clinical contact. For each subject, all inpatient and outpatient medical records of any local health care provider will be searched for vital status at last clinical contact. For deceased patients, all death certificates will be reviewed regardless of the patient location at death.

We also identified two Olmsted County residents (controls) without VTE matched by age and gender to each definite or probable case within the 1996-2000 cohort to perform a case-control study.

Description

No eligibility criteria

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Incident Cohort with VTE
Olmsted County, Minnesota residents with with a first-lifetime deep vein thrombosis (DVT) or pulmonary embolism (PE) during the five year period, 1996-2000.
Controls without VTE
Two Olmsted County, Minnesota residents without venous thromboembolism (VTE) were matched by age and gender to each definite or probable case of VTE within the 1996-2000 cohort.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean time interval between commencing unfractionated heparin therapy and achieving a therapeutic activated partial thromboplastin time (aPTT)
Time Frame: Day 1 in hospital
The time interval (minutes) was measured retrospectively, using the electronic medical record for each subject.
Day 1 in hospital

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: John Heit, MD, Mayo Clinic

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2001

Primary Completion (Actual)

May 1, 2009

Study Completion (Actual)

May 1, 2009

Study Registration Dates

First Submitted

February 13, 2001

First Submitted That Met QC Criteria

February 12, 2001

First Posted (Estimate)

February 13, 2001

Study Record Updates

Last Update Posted (Estimate)

December 6, 2012

Last Update Submitted That Met QC Criteria

December 5, 2012

Last Verified

December 1, 2012

More Information

Terms related to this study

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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