Spontaneous Retroperitoneal Hemorrhage During Oral Anticoagulant Therapy

To the Editor. —In a recent report in the Archives Errichetti et al1described their 4½-year experience with oral anticoagulant therapy in 141 patients. The incidence of major hemorrhagic complications in this series was 5% of the treatment courses. We would like to emphasize that the incidence of these complications diminishes as the number of patients studied increases; on the other hand, unusual and life-threatening hemorrhagic complications are most frequently seen in large series of patients and/or when patients are being managed for extended periods, as our figures suggest. From 1974 to 1983, 2,012 patients receiving oral anticoagulant therapy were treated in our anticoagulant clinic. Forty-eight percent of these courses were of six months' duration or less, corresponding to deep venous thrombosis of the lower extremities, pulmonary embolism, and cerebro vascular disease, whereas 52% represented long-lasting treatment courses in patients with valvular heart disease with one or more embolic