Assessment of the mean time in the therapeutic INR range and the SAME-TT2R2 score in patients with atrial fibrillation and cognitive impairment

INTRODUCTION    Most patients with atrial fibrillation (AF) are elderly and may have an increased risk of cognitive disorders. Low mean values of the therapeutic international normalized ratio (INR) range (TTR) (≤60%) are associated with increased risk of stroke, vascular events, and bleeding complications.
OBJECTIVES    The aim of the study was to evaluate the efficacy of long-term anticoagulant therapy in patients treated with vitamin K antagonists (VKAs), depending on their cognitive functions. In addition, we used the SAMe-TT2R2 risk score to predict the risk of ineffective anticoagulation.
PATIENTS AND METHODS The analysis comprised 154 patients (68 men and 86 women; mean age, 76 ±10 years) with AF and indications for long-term therapy with VKA (CHA2DS2-VASc score ≥1, HAS-BLED score <3). Cognitive functions were evaluated using the Mini-Mental State Examination (MMSE) score. The efficacy of VKA therapy was determined by the TTR values from the preceding 6 months of treatment. We used the SAMe-TT2R2 score to identify patients who were likely to have poor INR control.
RESULTS    Depending on the number of MMSE points, patients treated with VKAs were divided into 2 groups: patients with normal cognitive functions (MMSE score ≥27; n = 62) and those with cognitive impairment (MMSE score <27; n = 42). Despite the fact that all patients had indications for anticoagulant therapy, 50 patients (32%) received no VKAs on admission. The mean TTR value exceeded 60% in 61% of patients with an MMSE score of 27 points or higher, whereas mean TTR value was 28% in patients with an MMSE score of less than 27 (P <0.0001). Patients with a SAMe-TT2R2 score of 0 to 1 had higher TTR values than those with a SAMe-TT2R2 score of 2 or higher (r = –0.24; P <0.05 ). The cognitive status was significantly more impaired in patients with persistent and permanent AF compared with patients with paroxysmal AF (MMSE score, 25.8 ±3.7 vs 28.6 ±2; P <0.0001).
CONCLUSIONS    Cognitive disorders in patients with AF significantly reduce the efficacy of VKA therapy. The decision to administer VKA treatment should be based not only on the CHA2DS2-VASc and HAS-BLED scores, but also on the SAMe-TT2R2 score and the evaluation of the patient’s cognitive functions.