THE SIGNIFICANCE OF HEMATURIA IN THE ANTICOAGULATED PATIENT

Background: There have been many case reports of substantial renal disease in association with anticoagulation, yet the intensity of anticoagulation has changed over the years. In 1986, the American College of Chest Physicians and the Heart, Lung, and Blood Institute recommended a decrease in anticoagulation intensity. In addition, a variety of new methods to investigate hematuria have evolved, including computed tomography and red blood cell morphologic analysis. Because of these developments, we initiated a prospective study to evaluate the relationship between anticoagulation, microscopic hematuria, and major genitourinary tract disease. Methods: To determine the incidence, prevalence, and cause of microscopic hematuria, patients receiving longterm anticoagulation therapy and controls not receiving such therapy were monitored with monthly urinalyses in a 2-year prospective study. Patients who developed hematuria were further studied for genitourinary tract disease. The incidence of hematuria was analyzed with regard to relative levels of anticoagulation. Results: The incidence of hematuria in the anticoagulated and control groups was 0.05 and 0.08 per 100 patient-months, respectively. The prevalence of hematuria was 3.2% in the anticoagulated group and 4.8% in the control group. Genitourinary tract disease was identified in 81% of patients with more than one episode of microscopic hematuria, and the cause of hematuria did not vary between groups. There was no correlation between the level of anticoagulation and the incidence of hematuria. Conclusions: Anticoagulation at currently recommended levels does not predispose patients to hematuria. Identifiable genitourinary tract disease is present in the majority of anticoagulated patients with microscopic hematuria.