A prospective validation of the SAME-TT2R2 score: how to identify atrial fibrillation patients who will have good anticoagulation control on warfarin

Stroke prevention, achieved with oral anticoagulation therapy (OAT), is central to the management of patients with atrial fibrillation (AF). Well-managed OAT, as reflected by a long time in therapeutic range (TTR), is associated with good clinical outcomes. The SAME-TT2R2 score has been proposed to identify patients who will maintain a high average TTR on vitamin K antagonists (VKA) treatment. The objective of the study was to validate this score in a cohort of AF patients followed by an anticoagulation clinic. We applied the SAME-TT2R2 score to 1,089 patients with AF on VKAs followed by two anticoagulation clinics. The median TTR overall for the whole cohort was 73.0 %. There was a significant decline in mean (or median) TTR in relation to the SAME-TT2R2 score (p = 0.042). When the SAME-TT2R2 scores were categorized we find a TTR 74.0 % for score a parts per thousand currency sign2 and 68.0 % for score > 2 (p = 0.006). The rate of major bleeding events and stroke/TIA was 1.78 x 100 patient-years (pt-yrs) and 1.26 x 100 pt-yrs, respectively. No relationship exists between the SAME-TT2R2 score and adverse events. We describe the first validation of the SAME-TT2R2 score in AF patients where, despite an overall good quality of anticoagulation, the SAME-TT2R2 score is able to identify the patients who are less likely to do well on VKA therapy if this is the chosen OAT.