Effect of an interactive voice response system on oral anticoagulant management.
BACKGROUND
Monitoring oral anticoagulants is logistically challenging for both patients and medical staff. We evaluated the effect of adding an interactive voice response system to computerized decision support for oral anticoagulant management.


METHODS
We developed an interactive voice response system to communicate to patients the results of international normalized ratio testing and their dosage schedules for anticoagulation therapy. The system also reminded patients of upcoming and missed appointments for blood tests. We recruited patients whose anticoagulation control was stable after at least 3 months of warfarin therapy. We prospectively examined clinical data and outcomes for these patients for an intervention period of at least 3 months. We also collected retrospective data for each patient for the 3 months before study enrolment.


RESULTS
We recruited 226 patients between Nov. 23, 2006, and Aug. 1, 2007. The mean duration of the intervention period (prospective data collection) was 4.2 months. Anticoagulation control was similar for the periods during and preceding the intervention (mean time within the therapeutic range 80.3%, 95% confidence interval [CI] 77.5% to 83.1% v. 79.9%, 95% CI 77.3% to 82.6%). The interactive voice response system delivered 1211 (77.8%) of 1557 scheduled dosage messages, with no further input required from clinic staff. The most common reason for clinic staff having to deliver the remaining messages (accounting for 143 [9.2%] of all messages) was an international normalized ratio that was excessively high or low, (i.e., 0.5 or more outside the therapeutic range). When given the option, 76.6% of patients (164/214) chose to continue with the interactive voice response system for management of their anticoagulation after the study was completed. The system reduced staff workload for monitoring anticoagulation therapy by 48 min/wk, a 33% reduction from the baseline of 2.4 hours.


CONCLUSIONS
Interactive voice response systems have a potential role in improving the monitoring of patients taking oral anticoagulants. Further work is required to determine the generalizability and cost-effectiveness of these results.
Oake
Natalie
N
Clinical Epidemiology Program, Ottawa Health Research Institute, The Ottawa Hospital, Ottawa, ON K1Y 4E9
van Walraven
Carl
C
Rodger
Marc A
MA
Forster
Alan J
AJ
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D019090:Case Management; D003661:Decision Support Techniques; D004334:Drug Administration Schedule; D016903:Drug Monitoring / Q000379:methods*; D004360:Drug Therapy, Computer-Assisted; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D011446:Prospective Studies; D012189:Retrospective Studies; D012648:Self Care / Q000379:methods*; D016896:Treatment Outcome; D014859:Warfarin / Q000008:administration & dosage*; D055815:Young Adult
D000925:Anticoagulants; D014859:Warfarin