Assessing the Predictive Value of the SAMe-TT2R2 Score for Poor Anticoagulation Control in a Diverse Ethnic Population

Abstract

Introduction: In Asian countries, warfarin is still widely used for stroke prevention in non-valvular atrial fibrillation compared to non-vitamin K antagonist oral anticoagulants (NOACs) due to its affordability. A tool such as the SAMe-TT₂R₂ is needed to determine the probability of achieving and maintaining good anticoagulation control with warfarin therapy. However, it requires validation in the Malaysian cohort. Therefore, the objective of our study is to validate the SAMe-TT₂R₂ score in predicting poor anticoagulation control in Malaysia. A time in therapeutic range (TTR) < 65% was used to determine poor anticoagulation control. Method: This retrospective cohort study was conducted from July 2022 to July 2023. Patients were enrolled in 2020 from 49 facilities located across Malaysia resulting in a total of 957 included patients. TTR was calculated using Roseendaal’s method. Results: The mean (SD) TTR and SAMe-TT₂R₂ score in the overall cohort is 65.2% (±24) and 5.5 (±0.9) respectively. Almost half of the population (43.7%) has the SAMe-TT₂R₂ score of 5. Having diabetes, ischemic heart disease, and increasing HAS-BLED and SAMe-TT₂R₂ score affects anticoagulation control on univariate analysis. However, after adjusting for demographics and clinical variables on multivariate analysis, only the SAMe-TT₂R₂ score as a continuous variable persists in predicting poor anticoagulation control. A SAMe-TT₂R₂ score cut-off point of >5 best predicts poor anticoagulation control with a sensitivity of 0.49 and a specificity value of 0.68. Conclusion: The SAMe-TT₂R₂ score, especially when exceeding 5, was associated with a higher likelihood of poor anticoagulation control, emphasizing its relevance in clinical assessment. However, its limited predictive capability, reflected by a C-statistic of 0.548, suggests the need for cautious interpretation and consideration of additional factors in anticoagulation management decisions. Continuous monitoring and personalized strategies are crucial for optimizing outcomes in this population.