Evaluation of Warfarin Management with International Normalized Ratio Self-Testing and Online Remote Monitoring and Management Plus Low-Dose Vitamin K with Genomic Considerations: A Pilot Study

• Published in: Pharmacotherapy 2013-11, Vol.33 (11), p.1136-1146
• Main Authors: Bussey, Henry I., Bussey, Marie, Bussey-Smith, Kristin L., Frei, Christopher R.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Anticoagulants - administration & dosage; Anticoagulants - adverse effects; anticoagulation; Biological and medical sciences; Blood Coagulation - drug effects; Blood Coagulation - genetics; cost; Disease Management; Drug Monitoring - methods; Drug Monitoring - standards; Female; genomics; Genomics - methods; Genomics - standards; home INR monitoring; Humans; International Normalized Ratio - methods; International Normalized Ratio - standards; Male; Medical sciences; Middle Aged; Pharmacology. Drug treatments; Pilot Projects; Prospective Studies; Remote Sensing Technology - methods; Remote Sensing Technology - standards; Self Care - methods; Self Care - standards; self-testing; vitamin K; Vitamin K - administration & dosage; warfarin; Warfarin - administration & dosage; Warfarin - adverse effects; Young Adult
• ISSN: 0277-0008; 1875-9114
• DOI: 10.1002/phar.1343

Study Objectives As better international normalized ratio (INR) control and self‐testing reduce events in warfarin‐treated patients, and vitamin K supplementation may improve INR control, our primary objective was to evaluate the effect of a system combining frequent INR self‐testing with online remote monitoring and management (STORM2) and low‐dose vitamin K supplementation on INR control; our secondary objectives were to assess the impact of STORM2 on clinician time and to evaluate the influence of pharmacogenomics on INR stability and warfarin dose after vitamin K supplementation. Design Prospective pre‐ and postintervention study. Setting Freestanding clinical research center. Patients Fifty‐five patients treated with long‐term warfarin therapy who were referred from four anticoagulation clinics and seven medical practices. Intervention All patients performed weekly INR self‐testing and received vitamin K 100 µg/day and online anticoagulation management for 1 year. Measurements and Main Results INR control and time required for anticoagulation management were assessed, and an analysis of warfarin dosing and INR stability by genetic polymorphism subgroup (vitamin K epoxide reductase complex 1 [VKORC1] and cytochrome P450 2C9 isoenzyme) was performed; vitamin K product content was also analyzed. The percentage of time that the INR is within the time in therapeutic range (TTR) improved from 56% before the intervention to 81% after the intervention (p