Epidemiology of first and recurrent venous thromboembolism: a population-based cohort study in patients without active cancer.

Contemporary data from population studies on the incidence and complications of venous thromboembolism (VTE) are limited. An observational cohort study was undertaken to estimate the incidence of first and recurrent VTE. The cohort was identified from all patients in the UK Clinical Practice Research Datalink (CPRD) with additional linked information on hospitalisation and cause of death. Between 2001 and 2011, patients with first VTE were identified and the subset without active cancer-related VTE observed for up to 10 years for recurrent VTE. The 10-year cumulative incidence rates (CIR) were derived with adjustment for mortality as a competing risk event. A total of 35,373 first VTE events (12,073 provoked, 16,708 unprovoked and 6592 active cancer-associated VTE) among 26.9 million person-years of observation were identified. The overall incidence rate (IR) of VTE was 131.5 (95% CI, 130.2-132.9) per 100,000 person-years and 107.0 (95% CI, 105.8-108.2) after excluding cancer-associated VTE. DVT was more common in the young and PE was more common in the elderly. VTE recurrence occurred in 3671 (CIR 25.2%). The IR for recurrence peaked in the first six months at around 11 per 100 person years. It levelled out after three years and then remained at around 2 per 100 person years from year 4-10 of follow-up. The IRs for recurrences were particularly high in young men. In conclusion, VTE is common and associated with high recurrence rates. Effort is required to prevent VTE and to reduce recurrences.