Epidemiology of Venous Thromboembolism

BACKGROUND:

The Venous Thromboembolism (VTE) Research Group has explored and studied the epidemiology of DVT and pulmonary embolism (PE) for more than 2 decades. The earliest analyses were done with the database from the Framingham Heart Study. Subsequent analyses were undertaken using the Nurses' Health Study.

More than 5 years ago the DVT FREE Registry was conceived. The concept was to accrue broad representation of patients with ultrasound-confirmed DVT throughout the US.

The Principal Investigator began initial work on this project by developing the case report form (CRF) with Co-Investigators. After the CRF was piloted and finalized, centers were recruited for participation. The enthusiasm in response to DVT FREE was overwhelming. The initial investigators meetings were conducted by videoconference shortly after September 11, 2001. Accrual of patients occurred much more rapidly than projected. Within 6 months, 5,451 patients were enrolled with ultrasound-confirmed DVT at 183 participating institutions.

Dr. Samuel Z. Goldhaber chaired the Publications Committee. The Master Paper was published in January 2004. 3 manuscripts on subgroups and 3 manuscripts on special populations were subsequently published under Dr. Goldhaber's supervision. The subgroup papers studied upper extremity DVT, the relationship between DVT and symptomatic DVT and PE, and predictors of massive DVT. The special populations papers studied gender differences in receiving prophylaxis, utilization of vena cava filters, and pregnancy.

Though the publication record is impressive in scope, much work remains to be done. The database is rich in information of critical importance to health care providers. The information contained within the database should be analyzed to provide more detailed analyses which will be used for risk factor assessment and for decision-making regarding the implementation of VTE prophylaxis.

For the current DVT FREE publication project, we will use the database to analyze findings that will yield 8 publications in special populations: 1) medically ill hospitalized patients, 2) cancer patients, 3) nonorthopedic general surgery patients, 4) orthopedic surgery patients, 5) long-haul travel patients, 6) COPD Patients, 7) Renal Patients, and 8) Elderly Patients.

PROJECT DESCRIPTION:

• Medically Ill Hospitalized Patients:

Medically ill hospitalized patients are the most important subgroup to study. These patients often do not receive guideline-recommended prophylaxis. We believe that medically ill hospitalized patients are underserved.

For this DVT FREE publication, we will exclude all patients who had surgery within the past 3 months. We will also exclude women who were pregnant or postpartum. All other patients will be included in these analyses. They will be stratified according to age, height, weight, body mass index (BMI), gender, and whether they received prophylaxis.

• Cancer Patients:

Cancer patients have received increasing attention because of the relationship between cancer and DVT. For example, the National Comprehensive Cancer Network (NCCN) organized a special committee to write consensus guidelines for prevention and treatment of DVT in this patient population.

For this DVT FREE publication, we will include all patients with cancer. We will also include whether the cancer was active and whether the patient is receiving ongoing radiation therapy or chemotherapy. These cancer patients will be stratified according to age, height, weight, BMI, gender, and whether they received prophylaxis.

• Nonorthopedic General Surgery Patients:

For this DVT FREE publication, we will include all nonorthopedic general surgery patients. These patients will have undergone surgery within the 3 months prior to DVT. We will also explore the type of surgery (excluding orthopedic surgery) and type of anesthetic that was used. These patients will be stratified according to age, height, weight, BMI, gender, and whether they received prophylaxis.

• Orthopedic Surgery Patients:

For this DVT FREE publication, we will include all orthopedic surgery patients. We will also include patients who suffered hip fracture, pelvic fracture, upper extremity fracture, lower extremity fracture, or other fracture within 30 days prior to enrollment. We will also include patients with major trauma to the spine, pelvis, or upper or lower extremities. These patients will be stratified according to age, height, weight, BMI, gender, and whether they received prophylaxis.

• Congestive Heart Failure (CHF)
• COPD Patients:

For this DVT FREE publication, we will include all patients with COPD. These patients will be stratified according to age, height, weight, BMI, gender, and whether they received prophylaxis.

• Renal Patients:

For this DVT FREE publication, we will include all renal patients. These patients will be stratified according to age, height, weight, BMI, gender, and whether they received prophylaxis.

• Elderly Patients:

For this DVT FREE publication, we will include all elderly patients. For this study we will define elderly as 70 years of age or older. These patients will be stratified according to age, height, weight, BMI, gender, and whether they received prophylaxis.

Inclusion criteria

• Ultrasound-confirmed DVT patients from 183 institutions.