Background: Vitamin K antagonists, despite their tight therapeutic spectrum and the fear of bleeding complications, were long the most important drugs used in anticoagulant therapy. The aim of this study was to evaluate the quality of anticoagulant therapy and its relation with bleedings in everyday clinical practice.
Material and Methods: We analyzed the data of 272 patients with non-valvular atrial fibrillation treated in our county hospital using retrospective data collection of the last 1008±384 days. The INR (International Normalized Ratio) values and the time in therapeutic range (TTR) were analyzed. We asked patients about bleeding complications and searched the medical records.
Results: The TTR proved to be 64% and there was no statistically significant difference between that of 252 (92.7%) patients taking acenocoumarol and 20 (7.3%) on warfarin. Analyzing various factors leading to TTR under 70%, we found that none of them have a significant impact. Significantly more bleeding events occurred in the first 3 months after the initiation of anticoagulant therapy and in patients with TTR under 70%, but the latter was not significant after adjustment for factors influencing bleeding (OR 1.607, CI 0.571–4.522, p=0.392).
Conclusions: Although the present study’s TTR values were similar to those found in the warfarin branch of various large-scale international trials and in real-life settings, further improvement of vitamin K antagonist therapy are ne­cessary. As the possibilities for this are limited, we believe that the new type anticoagulant agents have a place in everyday clinical practice.

Keywords: Administration, Oral, Acenocoumarol, Aged, Anticoagulants - adverse effects, Atrial Fibrillation - drug therapy, Female, Hemorrhage - pathology, Humans, Hungary, Male, Retrospective Studies, Statistics, Nonparametric, Time Factors, Vitamin K - antagonists & inhibitors, Warfarin