Factors determining adherence to anticoagulant therapy in patients with atrial fibrillation

Aim. To identify risk factors for low adherence and develop a scale for its pre­diction. To evaluate the association of the predictive score with actual low adherence according to the 8-item Morisky Medication Adherence Scale, self-drug withdrawal, and adverse outcomes in patients with atrial fibrillation (AF).

Material and methods. The study included patients with AF and a high risk of thromboembolic events according to the CHA2DS2-VASc scale, who were hospitalized from January 2011 to December 2017. Potential risk factors for non-adherence, selected from the literature, were tested in a multivariate regression analysis followed by the development of an adherence prediction scale. The asso­ciation of predicted low adherence with actual adherence was assessed.

Results. The study included 199 patients. The analysis identified following predictors of low adherence: low income, history of bleeding, prior stroke, 4 positive responses to the adherence questionnaire, warfarin. Based on these predictors, a scale for predicting adherence was developed, while a threshold value of 3 points was identified (sensitivity, 90,2%, specificity, 98,4%). A significant association of low predicted adherence on the developed scale with actual adherence and adverse outcomes was demonstrated.

Conclusion. We have developed a scale for predicting adherence to anticoagulant therapy, and also determined its threshold value. In case of a high risk of low adherence, clinicians should try to increase adherence in order to prevent comp­lications.

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