Identifying patients who are likely to achieve and maintain a therapeutic international normalized ratio when prescribed a vitamin K antagonist (VKA) for stroke prevention in atrial fibrillation (AF) is challenging. The SAMe-TT₂R₂ score was developed on the basis of common clinical factors that can highlight patients who may be unable to achieve and maintain good anticoagulation control.

Our objective was to validate this score in a nationwide cohort of non-valvular AF patients.

We studied a cohort of consecutive Tunisian patients with non-valvular AF who had oral anticoagulation. The baseline and 6-months SAMe-TT2R2 score was calculated.

We included 915 patients, of whom 440 (48.1%) were male. Their median age was 65 years, median Cardiac failure or dysfunction, Hypertension, Age over 75 years [Doubled], Diabetes, Stroke [Doubled] - Vascular disease, Age between 65–74 and Sex category [Female] (CHA2DS2-VASc) score was 2 (0–9), and median Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly (HAS-BLED) score was 1 (0–5). The median SAME-TT2R2 score was 2 (0–8). At 12 months, the mean±standard deviation time in therapeutic range was 48.9%±28.7% overall, and 110 patients (12.0%) had a time in therapeutic range value >65%. Patients with a SAME-TT2R2 score 0 to 1 had a mean time in therapeutic range of 49.3%±30.4%, whereas patients with a SAME-TT2R2 score ≥2 had a mean time in therapeutic range of 48.7%±28.0% (P 0.871). The odds ratio for having a low time in therapeutic range value was 1 (95% confidence interval, 0.9–1.0; P 0.871) for those patients with a SAME-TT2R2 score ≥2.

In a “real-world” cohort of patients with atrial fibrillation and oral anticoagulation with VKA, there was no clinical value evidence of the SAME-TT2R2 score for the identification of patients who would have poor-quality anticoagulation.