Background: The quality of anticoagulation control is an important determination of thromboembolism and bleeding in patients with non-valvular atrial fibrillation. Previous trials have shown that SAMe-TT₂R₂ score could be used for prediction of anticoagulation control.

Objective: To predict labile international normalized ratio (INR) by SAMe-TT₂R₂ score in Thai patients with non-valvular atrial fibrillation.

Materials and Methods: The author retrospectively studied patients with non-valvularatrial fibrillation at Pranangklao Hospital between January 2019 and October 2020.

Results: One hundred thirty patients were enrolled. The average ages of the patients were 67.5±10.2 years. The average SAMe-TT₂R₂ scores were 3.2±0.8 and the average CHA₂DS₂-VASc score was 3.3±1.4. Most patients had hypertension and dyslipidemia. Most patients were prescribed betablockers. Most patients had time in therapeutic range (TTR) lower than 65. The present study has shown that patients with SAMe-TT₂R₂ score of 3 or more has also had high proportion of labile INR with statical significance. The sensitivity, specificity, positive predictive value, and negative predictive value of different cut-offs of SAMe-TT₂R₂ score greater than 2 and SAMe-TT₂R₂ score when excluding race showed improvement of the sensitivity and specificity for prediction of labile INR.

Conclusion: Labile INR was predicted by SAMe-TT₂R₂ score and the sensitivity and specificity increased in SAMe-TT₂R₂ score when excluding race.

Keywords: SAMe-TT₂R₂ score; Non-valvular atrial fibrillation; Anticoagulation control

DOI: doi.org/10.35755/jmedassocthai.2021.06.12415

Received 5 February 2021 | Revised 16 April 2021 | Accepted 20 April 2021