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Multi-Center Human Alert Trial to Prevent DVT and PE

This study has been completed.
Information provided by:
Brigham and Women's Hospital Identifier:
First received: December 7, 2006
Last updated: January 29, 2009
Last verified: January 2009
To evaluate physician response to human alerts that inform the clinician that his/her patient may be eligible for thromboprophylaxis. Medical records are reviewed to evaluate prescribing decision and to evaluate rates of venous thromboembolism.

Condition Intervention
Pulmonary Embolism
Deep Vein Thrombosis
Behavioral: Human Alert

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Prospective
Official Title: Physician Alerts to Prevent DVT and Pulmonary Embolism in Hospitalized Patients

Resource links provided by NLM:

Further study details as provided by Brigham and Women's Hospital:

Primary Outcome Measures:
  • Clinically diagnosed DVT and/or PE [ Time Frame: 90 days ]

Secondary Outcome Measures:
  • Mortality [ Time Frame: 30 and 90 days ]
  • Hemorrhagic events [ Time Frame: 30 and 90 days ]

Enrollment: 2496
Study Start Date: March 2006
Study Completion Date: August 2008
Primary Completion Date: August 2008 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
Physicians alerted about their high risk patients who are not receiving any VTE prophylaxis.
Behavioral: Human Alert
An alert from study staff informing a physician that his/her patient is at high risk for DVT and/or PE, but is not receiving any prophylaxis.
No Alert
Physicians not alerted about their high risk patients who are not receiving any VTE prophylaxis.
Behavioral: Human Alert
An alert from study staff informing a physician that his/her patient is at high risk for DVT and/or PE, but is not receiving any prophylaxis.

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Detailed Description:

Background Information and Rationale for the Study:

Venous thromboembolism (VTE) is often avoidable in hospitalized patients because proven prevention strategies have been established for patients at risk. North American and European prophylaxis guidelines have been widely disseminated. However, despite intensive educational efforts, VTE prevention remains underutilized.

At Brigham and Women's Hospital, we undertook a comprehensive program aimed at increasing the frequency of VTE prophylaxis in high risk patients. This novel strategy required: 1) devising a risk score that reliably and quickly identified patients at high risk of VTE, and 2) conducting a randomized controlled trial in which high risk patients without prophylaxis were randomized into an intervention or control group. The intervention group's physicians received a single alert explaining that the patient was at high risk, was not receiving prophylaxis, and urged that prophylaxis be selected from a template of available pharmacological and mechanical options. In contrast, the control group's physicians received no alert.

Each of 8 common risk factors was weighted according to a point scale. At least 4 score points were required to be deemed at "high risk" for VTE.

3 of the 8 risk factors were considered major and were assigned a score of 3 points each:

  1. Cancer
  2. Prior VTE
  3. Hypercoagulability

One of the 8 risk factors, surgery, was considered intermediate and was assigned a score of 2.

4 of the 8 risk factors were considered minor and were assigned a score of 1 point each:

  1. Advanced age (> 70 years of age)
  2. Obesity (Body Mass Index > 29)
  3. Bed rest
  4. Hormone replacement therapy or oral contraceptives

There were 2,506 patients in the randomized controlled trial of a computer alert: 1255 in the intervention group and 1251 in the control group. The incidence of symptomatic VTE at 90 days was high: 8.2% in the control group. This high incidence validates the 8 risk factor and point score methodology.

The intervention group had an overall 41% reduction in VTE, without any increase in major bleeding. There was a 60% reduction in the incidence of symptomatic pulmonary embolism.

Identification of Patients at Risk for Venous Thromboembolism (VTE):

A VTE risk profile will be computed for each hospitalized patient using 8 common risk factors. Each risk factor is weighted according to a point score. To be included in this trial, the point score must equal or exceed 4 points.

Minor (Low) Risk Factors (1 POINT each):

  • Advanced Age (>70 years of age)
  • Obesity (BMI >29, or the presence of the word "obesity" in admission exam notes)
  • Bed rest / Immobility (not related to surgery)
  • Female Hormone Replacement Therapy or Oral Contraceptives

Intermediate Risk Factor (2 POINTS each):

· Major Surgery (> 60 minutes)

Major (High) Risk Factors (3 POINTS each):

  • Cancer (active)
  • Prior VTE
  • Hypercoagulability

Increased VTE risk is defined as a cumulative VTE risk score 4, so that patients with at least 1 major risk factor (cancer, prior VTE, or hypercoagulability) plus at least 1 additional intermediate risk factor (major surgery or bed rest) or minor risk factor (advanced age, obesity, or hormone replacement therapy/oral contraceptives) become eligible. In the absence of a major risk factor, patients with 1 intermediate risk factor plus at least 2 minor risk factors become eligible.

Screening for Venous Thromboembolism Prophylaxis:

If the cumulative VTE risk score is ³4, orders are reviewed to detect ongoing mechanical or pharmacological prophylactic measures. Mechanical prophylactic measures include graduated compression stockings and intermittent pneumatic compression devices. Pharmacological prophylactic measures include unfractionated heparin, enoxaparin, dalteparin, fondaparinux, tinzaparin, and warfarin.


Randomization Envelopes containing the statement "ALERT" (Intervention) or "NO ALERT" (Control) will be provided by Harvard Clinical Research Institute (HCRI), to randomize patients who meet all inclusion criteria.

The intervention is informing the responsible physician that: 1) his or her patient is at high risk for VTE, 2) is not receiving prophylaxis, and 3) VTE prophylaxis is recommended. For control patients, VTE prevention guidelines are available, but no specific prompt is provided to use them.

Follow Up:

Ninety-day follow-up is performed in all study patients by medical record review and through contact with the subject's Primary Care Physician.

Data Collection and Study Endpoints:

The primary endpoint is clinically diagnosed DVT or PE at 90 days. Safety endpoints include total mortality and hemorrhagic events at 30 and 90 days, respectively. We define major bleeding as intracranial, intraocular, retroperitoneal, pericardial, or bleeding that requires surgical intervention or that resulted in a hemoglobin loss greater than 3 g/l.

DVT is diagnosed if there is loss of vein compressibility by ultrasound or a filling defect by CT scan or by conventional contrast venography. PE is diagnosed by a positive contrast chest CT scan, a high-probability ventilation perfusion scan, or conventional pulmonary angiogram.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
Hospitalized patients that have a cumulative VTE risk score of 4 or more with no orders for prophylactic measures.

Inclusion Criteria:

  • Patients > 18 years of age
  • Cumulative VTE risk score > 4
  • Absence of pharmacologic or mechanical prophylaxis orders
  • Patients from medical or surgical Services

Exclusion Criteria:

  • VTE risk score <4
  • Current active pharmacologic or mechanical prophylaxis order
  • Patients from the Department of Neurology, Newborn Service, Rehab Units, and Neonatal Intensive Care Unit (NICU).
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00409136

  Show 26 Study Locations
Sponsors and Collaborators
Brigham and Women's Hospital
Principal Investigator: Samuel Z. Goldhaber, MD Brigham and Women's Hospital
  More Information

Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Samuel Z. Goldhaber, MD, Brigham and Women's Hospital Identifier: NCT00409136     History of Changes
Other Study ID Numbers: 2005-P-002527
Study First Received: December 7, 2006
Last Updated: January 29, 2009

Keywords provided by Brigham and Women's Hospital:
Deep Vein Thrombosis
Pulmonary Embolism
Venous Thromboembolism

Additional relevant MeSH terms:
Pulmonary Embolism
Venous Thrombosis
Embolism and Thrombosis
Vascular Diseases
Cardiovascular Diseases
Lung Diseases
Respiratory Tract Diseases processed this record on April 28, 2017