Deep Vein Thrombosis: Incidence and Prevalence
General Adult Population
The incidence of venous thromboembolism (VTE) in the general adult population is approximately 1 per 1,000 annually, with deep vein thrombosis (DVT) specifically occurring at a rate of approximately 5 per 10,000 person-years. 1, 2, 3
Age-Related Patterns
- The incidence of DVT increases dramatically with age, rising from 2-3 per 10,000 person-years at ages 30-49 to approximately 20 per 10,000 person-years at ages 70-79 3
- Rates increase sharply after age 45 years, with most pulmonary embolism cases occurring between ages 60-70 in clinical studies 1, 2
- The age-related increase is particularly pronounced for pulmonary embolism among hospitalized patients 4
Sex Distribution
- DVT incidence is slightly higher in men than women in older age groups 2
- Overall incidence is similar between males and females in the general population, with male incidence of 0.51 per 1,000 subjects per year and female incidence of 0.38 per 1,000 subjects per year 5
Provoked vs. Unprovoked Events
- Approximately 40% of DVT cases are idiopathic (unprovoked), occurring without identifiable risk factors 3
- The remaining 60% are secondary (provoked) DVT associated with identifiable risk factors 5
High-Risk Groups
Hospitalized Patients
Hospitalized patients face dramatically elevated risk, with an incidence of 960.5 per 10,000 person-years—more than 100 times greater than community residents. 4
- The incidence among hospitalized medical patients ranges from 10-30% when screened systematically 6
- Approximately 50-70% of symptomatic VTE events and 70-80% of fatal pulmonary emboli occur in acutely ill medical patients 1
- The 30-day mortality of patients suffering a thrombotic event exceeds 25% 1
Elderly Patients
- VTE is predominantly a disease of older individuals, with incidence increasing substantially beyond age 60 years 1
- The dramatic age-related increase emphasizes the need for heightened vigilance in elderly hospitalized patients 4
Pregnant Women
Among pregnant individuals who develop venous thrombosis, approximately 60% are found to have the Factor V Leiden mutation, making inherited thrombophilia a major contributor in this population. 7
- Pregnancy and the puerperium are established major risk factors for VTE 2
- The combination of pregnancy with inherited thrombophilia substantially amplifies risk 7
Cancer Patients
- Malignancy is associated with moderate to high risk of VTE 6
- Cancer was identified as a risk factor in 9.6% of DVT cases in one clinical series 5
- History of malignancy is a recognized independent risk factor for VTE in hospitalized medical patients 1
Inherited Thrombophilia
Factor V Leiden is the most common hereditary thrombophilic risk factor, present in approximately 5% of Caucasians and found in 15-20% of individuals with an initial episode of VTE. 1, 7
Factor V Leiden Mutation
- Approximately 5% of non-Hispanic whites, with lower prevalence in Hispanic-Americans (lower rates) and African-Americans (lower rates), and virtual absence in Africans and Asians carry the heterozygous mutation 1, 7
- Heterozygotes have a 4- to 7-fold increased risk for initial VTE, with lifetime risk of approximately 10% 1, 7
- Homozygotes face an 80-fold increased risk for VTE, with lifetime risk exceeding 80% 1, 7
- In selected populations (age <50 years and/or recurrent thrombosis), up to 40% carry the Factor V Leiden genotype 7
Prothrombin G20210A Mutation
- The prothrombin G20210A mutation is the second most common heritable risk factor for VTE, present in approximately 6% of individuals with an initial episode of venous thrombosis 8
- Heterozygosity occurs in approximately 2.2% of non-Hispanic whites, 2.2% of Hispanic whites, and 0.6% of African Americans 1, 8
- The mutation increases risk for initial VTE by 2-4 fold compared to the general population 1, 8
Compound Heterozygosity
- Individuals with both Factor V Leiden and prothrombin mutations (compound heterozygotes) occur at a rate of 22 per 100,000 in the general population 1
- Compound heterozygosity confers an estimated 20-fold increased risk for initial VTE 1, 8
Other Inherited Thrombophilias
- Deficiencies in antithrombin III, protein C, and protein S collectively account for 5-20% of VTE patients, depending on cohort selection 1, 7
- These previously recognized familial thrombophilias are less common than Factor V Leiden but carry strong thrombotic risk 7
Inflammatory Bowel Disease
- Inflammatory bowel disease is classified as a medical condition associated with moderate to high risk of VTE 6
- The inflammatory state contributes to hypercoagulability in these patients 6
Additional Risk Factors in Medical Patients
Modifiable Risk Factors
- Prolonged immobility and reduced Barthel Index score are associated with increased VTE risk 1, 6
- Obesity is an established endogenous risk factor 2, 6
- Surgery accounts for 28.1% of secondary DVT cases, making it the most frequent identifiable risk factor 5
Clinical Conditions
- Cardiac disease, respiratory disease, and infectious diseases are associated with moderate to high VTE risk 6
- Elevated C-reactive protein, D-dimer, and fibrinogen levels are probable risk factors 1
- Critical illness, fever, and tachycardia increase VTE risk 1
Historical Factors
- Previous history of VTE is a strong predictor of recurrent events, with 20% recurrence within 5 years and 30% within 10 years without continued anticoagulation 1
- Trauma accounts for 17.1% of secondary DVT cases 5
Clinical Implications
Post-Thrombotic Syndrome
- The risk of post-thrombotic syndrome is approximately 30% at 10 years following DVT 1
- Approximately 10% of patients develop venous stasis ulceration 1