[Quantification of the part allocated to the preventability of vitamin K antagonists therapy bleeding events].

A prospective cohort of patients with a high INR (>or=5) and being treated by vitamin K antagonists (VKA) was assessed in the Amiens University Hospital. One of the purposes of the study was to assess the preventability of the haemorrhages due to VKA. The preventability concept is not very used in France. Identifying the preventability part of a side effect of a drug needs an adapted and reliable tool. Although different methods of assessment of preventability have been developed, none of them is unquestionable. For the needs of our study, we built a scale of measure adapted from a scale of preventability already published by defining more accurately some items and by reducing the subjective part of the interpretation. We were able to confirm the relevance of our revised scale by testing it by two experts. After consensus on the conflicting data, two thirds of the severe bleedings were considered as "potentially or totally preventable". These data are in agreement with published data. Indeed the data found in the literature are concordant to consider that an important part of VKA bleedings events can be prevented by a better management of the treatment.