Background: In patients <21 years old with acute provoked venous thromboembolism (VTE), the optimal duration of anticoagulant therapy is unknown.
Aims: We sought to compare the net clinical benefit, as measured by the 1-year risks of symptomatic recurrent VTE and clinically-relevant bleeding, of a shortened (6-week) versus conventional (3-month) duration of anticoagulation for the treatment of first-episode acute provoked VTE in patients <21 years of age.
Methods: Following local institutional review board approval and with informed consent provided, patients <21 years old with acute provoked VTE were enrolled across 42 centers in 5 countries in an NIH-funded prospective, randomized, open-label, blinded-endpoint trial (Kids-DOTT, NCT00687882). Patients whose repeat imaging at 6 weeks post-diagnosis did not show complete veno-occlusion were randomized to discontinue anticoagulation or to continue for an additional 6 weeks. The primary efficacy and safety endpoints were symptomatic recurrent VTE and clinically-relevant bleeding within 1 year. The primary analysis was non-inferiority in the per-protocol (PP) and intention-to-treat (ITT) populations, for which 95% confidence intervals (CI) in the absolute risk differences (ARDs; 6-week minus 3-month risk) in both endpoints were evaluated.
Results: In both the PP (n=297) and ITT (n=417) populations, baseline patient and VTE characteristics (Table 1) were well-balanced between treatment arms. Kaplan-Meier estimated 1-year risks in the PP population were: primary efficacy, 0.66% (95% CI: 0.00%, 1.95%) [6 weeks] and 0.70% (95% CI: 0.00, 2.07%) [3 months]; primary safety, 0.65% (95% CI: 0.00%, 1.91%) [6 weeks] and 0.70% (95% CI: 0.00, 2.06%) [3 months]. The 6-week regimen was shown non-inferior to the 3-month regimen in both the PP and ITT populations (Figure 1).
Conclusions: For patients <21 years old with acute provoked VTE whose repeat imaging at 6 weeks shows no complete veno-occlusion, discontinuing anticoagulation is appropriate, with low risks of symptomatic recurrent VTE and clinically-relevant bleeding.
To cite this abstract in AMA style:Goldenberg NA, Schulman S, Kittelson JM, Abshire TC, Bonaca M, Casella JF, Dale RA, Halperin JL, Hamblin F, Kessler0 CM, Manco-Johnson MJ, Sidonio RF, Spyropoulos AC, Steg PG, Turpie AGG, Hiatt WR, Kids-DOTT Trial Investigators§ and the ATLAS Group . A Six-week versus Three-month Duration of Anticoagulation for Acute Provoked Venous Thromboembolism in Patients < 21 Years Old: Results of the Multinational Kids-DOTT Randomized Controlled Trial [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/a-six-week-versus-three-month-duration-of-anticoagulation-for-acute-provoked-venous-thromboembolism-in-patients-21-years-old-results-of-the-multinational-kids-dott-randomized-controlled-trial/. Accessed December 7, 2021.
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