[Anticoagulant clinics are they effective in France? Performance evaluation of six anticoagulant clinics concerning the management of vitamin K antagonists].

Purpose: Recent data show that the quality of anticoagulation evaluated in patients receiving vitamin K antagonists (VKA) is not optimal in France. The aim of this retrospective study was to estimate the performances of six French anticoagulant clinics that manage VKA treatments over a 3-year period, from 2009 to 2011.

Methods: All clinics used the same rule based software. We determined the time spent in the therapeutic range (TTR), a surrogate end-point of quality of treatment with VKA.

Results: The overall duration of follow-up was 2755 patient-years concerning 2385 patients. The time spent in the therapeutic range 2 to 3 assigned for 89% of the patients, was 73%. On the other hand the time spent in the therapeutic range for the other two INR ranges (2.5-3.5 and 3-4.5) concerning 11% of patients with prosthetic heart valve was lower (63.7% and 68.8% respectively) with an imbalance in favour of the time below the range. In this study, warfarin (Coumadine(®)) and fluindione (Previscan(®)) allowed an equivalent quality of anticoagulation. The 1728 patients of age ranged from 60 to 100 years spent more time in TTR than the 651 younger patients. The percentage of time spent with an INR greater than 5 was extremely reduced which is a guarantee of safety.

Conclusion: These results prove that anticoagulant clinics in France have the same good performances as their counterparts abroad. It can be assumed that a high TTR contributes to a low incidence of both bleedings and thrombosis.