Thromboembolism recurrence likely; consider it a chronic disease (MARVELOUS)

Reference

Khan F, Rahman A, Carrier M, et al, for the 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.

Synopsis

Researchers assembled 18 studies involving 7515 patients by searching 3 databases for studies in any language that reported follow-up data on patients with a first, unprovoked VTE who were treated for at least 3 months and then followed up for at least 9 months (range = 2 years - 10 years). The authors included both 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 a deep vein thrombosis, and 3.3% developed a pulmonary embolism. Over 10 years, the cumulative incidence of VTE was 36.1% (95% CI 27.8 - 45.0), deep vein thrombosis was 25.1% (17.2 - 33.7), and pulmonary embolism was 11.2% (95% CI 5.9 - 18.4). The confidence intervals for the 10-year figures are wide (and therefore the estimate is inexact) because only 3 studies of 1975 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.