[Warfarin treatment of venous thromboembolism].

Background: Warfarin treatment of venous thromboembolism is the most frequent cause of reported serious and fatal adverse events associated with drug therapy in Norway. We assessed quality of treatment during transfer from hospital to community-based care.
Material and Methods: 66 out of 100 consecutive patients with venous thromboembolism were studied by a retrospective survey that included data from hospital records and a questionnaire survey.
Results: Time in therapeutic range was 57% during the first four weeks. Undertreatment was the most frequent deviation. Some patients reported a long time lag from INR measurement to dose prescription in community care; 42% did not receive written treatment information. There were six recurrences, but no serious or fatal bleeding complications during one year of observation. Patient satisfaction with information and treatment organisation was high.
Interpretation: There is room for improvement of patient information and treatment quality in outpatient care in our area.