Epidemiology of venous thromboembolism in the Framingham Heart Study

Abstract

Background: Reports of the crude incidence of venous thromboembolism (VTE) in Western countries vary widely. Data regarding risk factors, incidence and recurrence of VTE from deeply-phenotyped community-based cohort studies are needed.

Objectives: To study the incidence, associated mortality, and predisposing factors of VTE in the prospective, longitudinal community-based Framingham Heart Study.

Patients/methods: The study sample consisted of the Framingham Heart Study Original, Offspring, Third Generation, and Omni cohorts (N=9754). Incidence rates (IR) were standardized to the 2000 US population. Cox proportional hazards regression models were used to study risk factor associations.

Results: During 1995-2014 (total follow-up time 104,091 person-years [median 9.8 (range 0-20) years]), 297 incident VTE events were observed. Age-adjusted IR of VTE was 20.3/10,000 (95% CI 17.9-22.6). Of the events 120 (40%) were pulmonary embolism (PE) and 177 (60%) were deep venous thrombosis (DVT); 29% were unprovoked, 40% provoked, and 31% cancer-related. Cancer-related VTE was associated with high mortality at 30days (24.2%), 1year (66.3%), and 5years (75.6%). In multivariable models, age and obesity, but no other traditional cardiovascular risk factors, were significantly associated with VTE (hazard ratio [HR] per 10-year increase in age 1.69, 95% CI 1.48-1.92; HR for obesity (BMI≥30kg/m(2)) 1.88, 95% CI 1.44-2.45).

Conclusions: We provide data on the epidemiology of VTE. VTE is associated with significant mortality, and prognosis after cancer-related VTE is particularly poor. Traditional cardiovascular risk factors beyond age and obesity are not associated with VTE.

Keywords: Deep venous thrombosis; Epidemiology; Incidence; Mortality; Pulmonary embolism; Risk factors; Venous thromboembolism.

Figure 1. Crude IR according to age group

Crude incidence rate (per 10,000 person-years) of VTE according to age groups. Vertical bars represent 95% confidence intervals of incidence rates.

Figure 2. Mortality according to VTE subgroup

Mortality according to VTE subgroup [unprovoked (U), provoked (P), cancer-related (C)]. Event-free survival probability is presented on the Y-axis and time in years on the X-axis. Number of persons at risk per group across time is presented underneath the figure.