Evaluation of SAMe-TT₂R₂ score and other clinical factors influencing the quality of anticoagulation therapy in non-valvular atrial fibrillation: a nationwide study in Spain

<p><b>Objective</b>: To assess the major clinical factors affecting the quality of anticoagulation and evaluate the predictive value of the SAMe-TT₂R₂ score to identify patients who will achieve a high average time in therapeutic range (T.T.R.) with vitamin K antagonist (V.K.A.) treatment. <b>Research design and methods</b>: This observational, cross-sectional, retrospective and nationwide multicenter study included 1524 patients from the primary care setting with non-valvular atrial fibrillation receiving V.K.A. (≥12 months). We performed a bivariate analysis to identify factors individually associated with the T.T.R. and a multiple regression analysis to identify the independent predictive factors. For the validation of the SAMe-TT₂R₂ score, the receiver operating characteristic (R.O.C.) curve was calculated and the Hosmer–Lemeshow test was used to test calibration. <b>Results</b>: A total of 94.8% of patients received acenocumarol (4.8% warfarin). A progressive decrease in mean T.T.R. was found when the SAMe-TT₂R₂ score increased from 0 points (72.1 ± 17.1%) to 4 points (64.1 ± 23.2%), <i>p</i> < 0.001. Other risk scores (CHADS₂ and CHA₂DS₂-VASc, HAS-BLED) were also associated with the mean T.T.R. We found a significant association between low T.T.R. and the following clinical factors: female sex, three or more comorbidities, amiodarone treatment, dietary habits, bleeding history and the intake of ≥7 tablets per day besides V.K.A. (<i>p</i> < 0.01). Regarding SAMe-TT₂R₂ score validation, the R.O.C. curve showed significant capability, although not high, of discriminating good anticoagulation control (T.T.R. ≥65%) with an area under the curve of 0.562 (95% C.I. 0.533–0.592, <i>p</i> < 0.001) which increased, remaining modest, to 0.594 (95% C.I. 0.564–0.624, <i>p</i> < 0.001) when the factors not included in SAMe-TT₂R₂ score were added. <b>Conclusion</b>: In this cohort, the SAMe-TT₂R₂ score had a significant, although modest, ability to assess the likelihood of good international normalized ration (I.N.R.) control, and its predictive value might slightly improve by adding other simple clinical factors. Further research is needed to refine the predictive scales.