Interferência de alimentos ricos em vitamina K na terapia com varfarina em pacientes do Hospital Universitário Onofre Lopes

Abstract

Chronic oral anticoagulation is a therapeutic strategy to prevent and treat thromboembolism in various clinical conditions. Warfarin is an anticoagulant that acts as a vitamin K antagonist, so the consumption of foods with high amounts of this vitamin becomes an important factor influencing the stability of oral anticoagulation. The present study aimed to evaluate the interference of foods rich in vitamin K on the anticoagulant action of warfarin, using as an evaluation parameter the International Normalized Ratio (INR) results. We selected 47 patients treated at the Onofre Lopes University Hospital outpatient clinic, from 2015 to 2018. These patients were evaluated in their entirety and also in 3 groups (below, within and above the therapeutic range), according to the values of INR. Data on the dietary frequency of vitamin K-rich foods and food intake score were obtained. In this study, it was observed that most patients were female (76.6%), with the main clinical indication of anticoagulant use for the metallic heart valve (57%). Furthermore, it was found that higher intake of foods with high vitamin K content contributed to a higher frequency of patients with INR values below the therapeutic range. Therefore, our results indicate that the influence of vitamin K rich food consumption on warfarin therapy is clinically relevant in clinical practice and should be recognized as an important and independent factor that interferes with the stability of anticoagulation.