Recurrence and mortality after first venous thromboembolism in a large population-based cohort

Background: Previous reports on recurrence and mortality rates after a first episode of venous thromboembolism (VTE) vary considerably. Advances in the management and treatment of VTE during the last 15 years may have influenced the rates of clinical outcomes. Aim: To estimate the rates of recurrence and mortality after a first VTE in patients recruited from a large population-based cohort. Method: From the Tromso study, patients (n = 710) with a first, symptomatic, objectively confirmed VTE were included and followed in the period 1994-2012. Recurrent episodes of VTE were identified from multiple sources and carefully validated by review of medical records. Incidence rates and cumulative incidence rates with 95% confidence intervals (CIs) of VTE recurrence and mortality were calculated. Results: The mean age of the patients was 68 years (range 28-102 years), and 166 (23.4%) had cancer at the time of first VTE. There were 114 VTE recurrences and 333 deaths during a median study period of 7.7 years (range 0.04-18.2 years). The risk of recurrence was highest during the first year. The overall 1-year recurrence rate was 7.8 (95% CI 5.8-10.6) per 100 person-years (PY), whereas the recurrence rate in the remaining follow-up period (1-18 years) was 3.0 (95% CI 2.4-3.8) per 100 PY. The overall 1-year all-cause mortality rate was 29.9 (95% CI 25.7-34.8) per 100 PY, and in those without cancer the corresponding rate was 23.6 (95% CI 17.8-31.3) per 100 PY. Conclusion: Despite advances in VTE management, the rates of adverse events remained fairly high, particularly in the first year following a first VTE.