Improved anticoagulant control in patients using home international normalized ratio testing and decision support provided through the internet

Aim: To compare anticoagulant control using self-testing and decision support provided via the internet with standard laboratory testing. Methods: A prospective comparative study of 41 patients on long-term warfarin. All patients were monitored using a laboratory-based service for at least 12 months prior to changing to self-testing using a portable testing device and online decision support. The level of anticoagulant control was assessed using the time the international normalized ratio (INR) was within the therapeutic range (TTR), the proportion of INR results in range and the interval between tests. This was a non-inferiority study. Results: There was no statistically significant difference between the two methods of anticoagulant control with a trend in favour of self-testing; the mean TTR was 72% vs 81%. However, a small cohort of patients with poor control (TTR 38%) during laboratory testing achieved a significant improvement (TTR 71%) using self-testing. The INR was above the therapeutic range for a similar time in both groups but below the range for a significantly shorter period during self-testing suggesting a lower risk of complication in this group. Conclusion: Self-testing with online computer decision support achieved anticoagulant control at least as good as laboratory management. Additional benefits of a home-based service make this an attractive option for selected patients.