A retrospective study was conducted on an unselected sample of patients on vitamin K antagonists (VKAs; phenprocoumon, acenocoumarol) in an outpatient setting in Austria. The main objective was to determine whether bleeding and thromboembolic events reported in randomised trials are comparable to the experience in clinical practice. In addition, we focused on differences between the two VKAs and the particular indications for treatment and influences of risk factors.
Total observation time was 10 years, the number of patients was 599 and the patient years-at-risk (pyr) was 1,856.
Severe bleeding occurred in 1.1 % pyr and the bleeding-related mortality was 0.1 %. Severe thromboembolic events occurred in 2.8 % pyr, with a rate of fatal events of 0.3 %. A significant increase in risk was found in patients older than 75 years concerning bleeding as well as thromboembolic events. Acenocoumarol showed significantly higher rates in life-threatening and fatal bleeding episodes in comparison to phenprocoumon.
The outcome of patients receiving VKA in an office setting is similar to that reported in the literature and the use of VKAs in this setting appears to be safe.