Therapeutic control of anticoagulant treatment.

Control of anticoagulant treatment was studied in 250 patients. One hundred and fifty patients receiving long-term anticoagulant treatment (group 1) were studied for 52 weeks and the remaining 100 (group 2) for 12 weeks after discharge from hospital. The desired British correlated ratio range was 2.5-3.3, and a range of 2.3-3.5 was classified as satisfactory. In group 1 a satisfactory ratio was obtained for 70% of the study period and 120 of the 150 patients were maintained within this range for over 60% of the time. In group 2 only half of the patients were maintained within the satisfactory range and for 50% of the study period or less. The time and effort expended in therapeutic control were more than most clinics could afford, and the results for group 2 were disappointing. The standard of long-term anticoagulant treatment should be improved by continuous review of control and by "therapeutic quality control."