Clinical significance of vitamin B 12 deficiency in the development of cognitive impairment in patients with a combination of atrial fibrillation and coronary artery disease on dual antithrombotic therapy

Atrial fibrillation (AF) and coronary artery disease (CAD) are independent risk factors for cognitive impairment (CI). Vitamin B 12 deficiency is considered a potentially reversible factor for cognitive decline, but the available literature data are contradictory.

Objective. To assess the impact of vitamin B 12 deficiency on cognitive function in patients with AF and CAD on dual antithrombotic therapy (DATT).

Materials and methods. This prospective open cohort study included 126 patients with AF and CAD (mean age 69.5 [63; 76] years, 62.7 % men) on DATT. They were divided into two groups: with vitamin B 12 deficiency (n=21) and without deficiency (n=105). All patients underwent cognitive assessment using the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Trail Making Test, Word fluency test, Word-List Recall, and Stroop color-word conflict. Levels of anxiety and depression were also assessed using the Beck Anxiety Inventory and the Hamilton Rating Scale for Depression, respectively.

Results. In the vitamin B 12 deficient group, the completion time for the third part of the Stroop Test was statistically significantly longer (205.0 [176.8; 248.0] s vs. 180.0 [148.0; 222.3] s, respectively; p=0.048). The difference remained statistically significant after excluding patients with anemia (p=0.049). According to the MMSE, the group without vitamin B 12 deficiency and anemia had a statistically significantly higher number of patients with normal scores (29–30 points) – 15 patients (18 %), whereas there were no such patients in the vitamin B 12 deficient group (p=0.037 between groups).

Conclusions. In patients with AF and CAD on DATT, vitamin B 12 deficiency is a modifiable risk factor for CI and is associated with selective executive dysfunction. Its early diagnosis may help improve cognitive function and quality of life.

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