Clinical Question

After stopping anticoagulation for venous thromboembolism (VTE), what is the likelihood of a subsequent VTE over 10 years?

Bottom Line

Perhaps it is time to start thinking about VTE as a chronic disease. Approximately one in 10 patients that have a VTE will have a second VTE over the next 12 months and almost four in 10 will have a second VTE over 10 years. The risk of developing deep venous thrombosis is 6.2% over one year and 25.1% over 10 years. The risk for pulmonary embolism is 3.3% over one year and 11.2% over 10 years. (Level of Evidence = 1a–)

Synopsis

Researchers assembled 18 studies involving 7,515 patients by searching three databases for studies in any language that reported follow-up data on patients with a first, unprovoked VTE who were treated for at least three months and then followed up for at least nine months (range = two to 10 years). The authors included observational and intervention trials. All studies were evaluated as being high quality. Over the first year following discontinuation of treatment, 10.3% of patients had a second VTE, 6.2% developed deep venous thrombosis, and 3.3% developed pulmonary embolism. Over 10 years, the cumulative incidence of VTE was 36.1% (95% CI, 27.8 to 45.0), deep venous thrombosis was 25.1% (95% CI, 17.2 to 33.7), and pulmonary embolism was 11.2% (95% CI, 5.9 to 18.4). The confidence intervals for the 10-year figures are wide (and therefore the estimate is inexact) because only three studies of 1,975 patients followed patients for 10 years, with dropouts along the way. There was some significant heterogeneity among the studies for some of the outcomes that could not be explained by initial VTE site, sex, or use of aspirin following anticoagulant treatment.

Study design: Meta-analysis (other)

Funding source: Government

Setting: Various (meta-analysis)

Reference: Khan F, Rahman A, Carrier M, et al.; MARVELOUS Collaborators. Long term risk of symptomatic recurrent venous thromboembolism after discontinuation of anticoagulant treatment for first unprovoked venous thromboembolism event: systematic review and meta-analysis. BMJ. 2019;366:l4363.