Better stability of acenocoumarol compared to warfarin treatment in one-year observational, clinical study in patients with nonvalvular atrial fibrillation.

Aim: To evaluate differences in the treatment quality between often used oral anticoagulants, warfarin and acenocoumarol in patients with nonvalvular atrial fibrillation (NVAF).

Methods: This was an observational, comparative, one-year clinical study, conducted in the Blood Transfusion Institute of Sarajevo, Bosnia & Herzegovina. All patients who were using warfarin/ acenocoumarol and monitored were eligible. Patients who met inclusion criteria (the age of 40-80, diagnosed NVAF, CHADS index score > or = 2, the planned long-term treatment) were includes in two parallel groups of 60 patients, composed according to the warfarin/acenocoumarol treatment as well as the gender and age. Routinely measured International normalised ratio (INR) values were the basic parameter for individual quality and stability assessment.

Results: All average, monthly INR values were in therapeutic range (2.0-3.0) in both therapeutic groups. There were no significant differences either in the number of therapeutic INR values per patient (50.53 +/- 23.72% vs. 51.74 +/- 26.68%, P = 0.795) or in individual quality of treatment: > 50% therapeutic INR values (60.0% vs. 64.9%, P = 0.721) and > 75% therapeutic INR values (18.3% vs. 22.8%, P = 0.714) in the warfarin and acenocoumarol group, respectively. Significantly better stability was determined for acenocoumarol as compared with warfarin treatment in terms of a longer period of the total observed time during which therapeutic INR values were stable (37.6% vs. 35.7%, P = 0.0002).

Conclusion: Both drugs have shown similar quality of individual anticoagulation control, but acenocoumarol have shown significantly better anticoagulation stability with therapeutic INR values covering significantly longer time of treatment.