Computerized management of oral anticoagulant therapy: experience in major joint arthroplasty.

OBJECTIVE Evaluation of the safety and potential cost savings of a computerized, laboratory-based program to manage inpatient warfarin thromboprophylaxis after major joint arthroplasty. DESIGN A consecutive-case study of adults. SETTING A tertiary care orthopedic institution. PATIENTS Patients requiring joint arthroplasty who had no recent episodes of thromboembolic disease, no mechanical heart valve, atrial fibrillation, severe liver disease or baseline international normalized ratio [INR] greater than 1.3 admitted over a 54-month period (July 1994-December 1998). All patients received a standard regimen of warfarin beginning on the evening after the operation. Four hundred and thirty randomly selected patients managed by the program were followed up by telephone survey 3 months after discharge. Patients exhibiting erratic responses to warfarin were withdrawn from the program and managed individually thereafter. INTERVENTION Major joint arthroplasty with warfarin therapy administered through the computerized program. MAIN OUTCOME MEASURES Test results maintained within the desired therapeutic range (INR 2.0-3.0), clinically severe bleeding episodes, readmission rates, clinically symptomatic and venographically proven episodes of venous thrombosis or pulmonary embolism. RESULTS Over the study period 5629 patients underwent joint arthroplasty; 5,372 patients were considered for the program; 332 patients were ineligible and were managed individually; 311 entered patients did not complete the program. This left 4,729 patients who completed the program. In 2932 (62%) patients test results were maintained in the desired therapeutic range. The major bleeding rate was less than 0.5%, the readmission rate was 3.8%, the deep venous thrombosis rate was 3.7% and the pulmonary embolism rate was 0.2% with no thromboembolic related deaths in the small sample cohort. CONCLUSIONS The majority of patients requiring warfarin thromboprophylaxis can be safely and effectively managed by this laboratory-based computerized program while in hospital. Significant potential cost savings in nursing time could be achieved.