Effectiveness of Smartphone Applications vs Conventional Care in Warfarin Therapy: A Randomized Controlled Trial on the Time in the Therapeutic Range

Objective: Warfarin is extensively used as an oral anticoagulant; however, its clinical application is complicated by a narrow therapeutic index. This investigation evaluated the efficacy of a drug reminder application versus traditional care in facilitating patients’ maintenance of the therapeutic range, as well as in stabilizing the time in the therapeutic range (TTR). Material and Methods: A single-blind randomized controlled trial recruited 40 warfarin users (≥3 months) with stable INR for 6 months. The intervention group received a smartphone app reminder. All INR values were collected for 6 months. Primary outcomes were TTR, INR, TTR during drug-drug interactions, and warfarin complications. Results: Forty patients were recruited between January 2021 and August 2023. The mean TTR was 66.11%±9.8% for the intervention group and 67.31%±18.08% for the control group. With analysis of covariance, the results were slightly better in the intervention group, but the differences were not statistically significant (95%CI = -5.67 – 1.92, P-value = 0.323). For the 6-month INR monitoring, 6 out of 8 patients who could maintain the therapeutic INR range were in the intervention group. There were no statistically significant differences in warfarin-related complications between the two groups (20% vs 15%, RR 1.333, 95%CI = 0.3413 – 5.2086, P-value = 0.6790). Conclusion: The drug reminder application likely improved the TTR, although without statistical significance. Further studies are needed to identify technology assistance in improving treatment outcomes.