Is Indefinite Anticoagulation After Unprovoked VTE Beneficial?

Discontinuing anticoagulation therapy following an unprovoked venous thromboembolism (VTE) puts individuals at a greater risk for recurrent VTE, according to a new analysis. In fact, 36% of those with unprovoked VTE who stop taking anticoagulants will experience a recurrent VTE within 10 years of treatment discontinuation.

To reach this conclusion, the researchers identified 18 randomized controlled trials and prospective cohort studies that included a total of 7515 participants. The participants had all completed at least 3 months of anticoagulation treatment following their initial unprovoked VTE, and the studies each measured the rate at which these participants had symptomatic recurrent VTE after discontinuing treatment.

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The researchers determined that the cumulative incidence for recurrent VTE was 16% at 2 years post-therapy discontinuation, 25% at 5 years post-therapy discontinuation, and 36% at 10 years post-therapy discontinuation. 

The absolute risk for recurrent VTE upon discontinuing anticoagulation therapy is greatest in the first year after treatment (10.3%). This risk decreases to 6.3% in the second year, then drops to 3.8% in years 3 to 5, and then to 3.1% in years 6 to 10.

According to the results, men are more likely than women to have recurrent VTE after stopping therapy. After 10 years of not taking therapy, the cumulative incidence for recurrent VTE was 41% among men and 29% among women.

Participants who had proximal deep vein thrombosis or pulmonary embolism plus deep vein thrombosis had a higher risk for recurrent VTE compared with those with isolated pulmonary embolism. Meanwhile, the risk for recurrent VTE after 1 year of treatment discontinuation was low among participants with distal deep vein thrombosis (1.9 %).

Recurrent VTE resulted in mortality in 4% of the cases.

“These estimates should inform clinical practice guidelines, enhance confidence in counseling patients of their prognosis, and help guide decision making about long-term management of unprovoked VTE,” the researchers concluded. 

“When weighed against current best estimates for risks and consequences of major bleeding if anticoagulation is continued, our results could be used to decide whether to consider indefinite anticoagulation for unprovoked VTE.”

—Colleen Murphy

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 [published online July 24, 2019]. BMJ. doi:10.1136/bmj.l4363.