The SAMe-TT2R2 score as an indicator of warfarin control for patients with deep vein thrombosis in Queensland, Australia.

Abstract

Oral anticoagulation options for patients with venous thromboembolism (VTE) include vitamin K antagonists like warfarin. Good warfarin control is linked to outcomes of therapy, and the SAMe-TT2R2 model has been reported to predict control in atrial fibrillation patients with scores ≥ 2 linked to poor control. There has been limited and conflicting data in VTE populations, therefore this study aimed at determining the predictive ability of this model in Australian patients with deep vein thrombosis. Retrospective data of patients receiving warfarin care at a private pathology clinic in Queensland was collected. The time in therapeutic range (TTR) and SAMe-TT2R2 score was calculated for individual patients. Mean TTR and patients with TTR ≥ 65% were used for analysis and comparison across patients categorised as a score of 0-1 and ≥ 2. Of the 533 patients, the majority had a SAMe-TT2R2 score of 0-1. No significant difference was found in mean TTR between patients with a score of 0-1 and ≥ 2 but there was a significantly higher percentage of patients with a TTR ≥ 65% between groups (93.8% vs. 69.2%, p < 0.0001, respectively). The SAMe-TT2R2 score may assist in identifying patients with VTE likely to achieve good control (TTR ≥ 65%), but further investigation is required to determine the most suitable model for predicting warfarin control in this population.