EFFECTIVENESS OF ANTICOAGULATION AMONG PATIENTS DISCHARGED FROM HOSPITAL ON WARFARIN

Objectives: To examine the effectiveness of anticoagulation among pati ents discharged from hospital on warfarin in the care of general pract itioners (GPs). Design and setting: A historical cohort with questionn aires to patients discharged from a major metropolitan teaching hospit al and their GPs. Participants: Patients discharged between 1 February 1995 and 31 January 1996 identified from hospital pharmacy records as being prescribed warfarin, and their treating GPs. Main outcome measu res: Frequency of testing and levels of international normalised ratio of prothrombin time (INR) within six months of discharge; level of IN R aimed at by GP; complication rates; and patient knowledge about anti coagulation. Results: Replies were received from 242 (68%) patients an d pathology records were examined for 195 (81%) of these. The median g ap between INR measures was seven days. The median of the median INR l evel for each patient was 2.4 (rising to 2.7 in patients with an artif icial heart valve); 24% of observed patient time was spent at an INR l evel of less than 2.0, 54% between 2.0 and 2.9, 18% between 3.0 and 3. 9 and 4% at an INR level of 4.0 or more. There were five confirmed maj or complications (equivalent to 5 per 100 patient-years). Twenty-seven per cent of patients answered at least eight of the 10 knowledge ques tions correctly: education level predicted knowledge, but there was no relationship between knowledge and INR level. Conclusions: Among this unselected group of patients whose anticoagulation was managed by GPs , there was a high frequency of laboratory testing, INR levels were co ntrolled safely and complication rates were comparable with those in p ublished reports.