A COMPUTERIZED INTERVENTION TO IMPROVE TIMING OF OUTPATIENT FOLLOW-UP- A MULTICENTER RANDOMIZED TRIAL IN PATIENTS TREATED WITH WARFARIN

Objective: To evaluate a computerized scheduling model that employs no nlinear optimization to recommend optimal follow-up intervals for pati ents taking warfarin. Design: Randomized trial. Setting: 5 anticoagula tion clinics. Patients/participants: 620 patients expected to receive warfarin for greater-than-or-equal-to 6 weeks. Interventions: Computer -generated recommendations for scheduling the next visit were presente d to or withheld from practitioners. Measurements and main results: Th e main outcome measures were the follow-up interval scheduled by the p rovider, the interval at which the patient actually returned to clinic , and the quality of anticoagulation control (computed as the absolute difference between the measured and target prothrombin times [PTRs] o r international normalized ratios [INRs]). Follow-up intervals schedul ed for the patients whose practitioners received computer-generated re commendations were significantly longer than those for control patient s (mean, 4.4 vs 3.5 weeks, p < 0.001), despite the fact that the pract itioners modified the suggested return interval by > 1 week on 40% of the visits. The interval at which the intervention group actually retu rned to clinic was also longer (mean, 4.4 vs 4.1 weeks, p < 0.05), eve n though the control patients tended to return at longer intervals tha n were scheduled by their practitioners. Control of anticoagulation wa s nearly the same among experimental and control patients. Life-threat ening complications occurred in the care of three experimental patient s-and one control patient, while other serious complications occurred in the care of 16 experimental patients and 17 control patients. Concl usions: Recommendations based on nonlinear optimization prompted clini cians to schedule less frequent follow-up for patients taking warfarin , with no deterioration in anticoagulation control. This approach to s cheduling can potentially reduce utilization while maintaining quality of care for patients who require long-term monitoring.