RESUMEN
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<0.0001), and time spent at extreme INR values of lower than 1.5 or higher than 5 was reduced from 3.1% to 0.4% (p=0.01). Clinician time was less than 10 minutes per four patient visits per month. Genetic polymorphisms did not correlate with INR stability or the increase in warfarin dose after vitamin K supplementation. The content of the vitamin K product, however, was only 34-76% of the labeled amount. Patients with the GG VKORC1 genotype required a higher warfarin dose than predicted by the genomic-based dosing chart in the warfarin package insert. CONCLUSION: The 25% point improvement in TTR with STORM2 is a greater improvement than reported previously with other efforts to improve TTR. STORM2 required a minimum amount of clinician time. Pharmacogenomics were not predictive of improved INR control or the magnitude of the warfarin dose after vitamin K supplementation, although the content of the product was unreliable. Patients with the GG VKORC1 genotype required a higher warfarin dose than predicted by the product information. The potential clinical impact of improved INR control with this method warrants comparisons with conventionally managed warfarin and with the new oral anticoagulants.
Asunto(s)
Monitoreo de Drogas/normas , Genómica/normas , Relación Normalizada Internacional/normas , Autocuidado/normas , Vitamina K/administración & dosificación , Warfarina/administración & dosificación , Adulto , Anciano , Anciano de 80 o más Años , Anticoagulantes/administración & dosificación , Anticoagulantes/efectos adversos , Coagulación Sanguínea/efectos de los fármacos , Coagulación Sanguínea/genética , Manejo de la Enfermedad , Monitoreo de Drogas/métodos , Femenino , Genómica/métodos , Humanos , Relación Normalizada Internacional/métodos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Estudios Prospectivos , Tecnología de Sensores Remotos/métodos , Tecnología de Sensores Remotos/normas , Autocuidado/métodos , Warfarina/efectos adversos , Adulto JovenRESUMEN
STUDY OBJECTIVE: International normalized ratio self-testing with online remote monitoring and management (STORM2) is an alternative to anticoagulation clinic management, but the patient's perspective of this method has not been evaluated in the United States; thus we sought to evaluate the impact of STORM2 on patient satisfaction, time, and cost. DESIGN: Prospective pre- and postintervention study. SETTING: Freestanding clinical research center. PATIENTS: Forty-three patients treated with long-term warfarin therapy and monitored initially in the anticoagulation clinic setting and then with STORM2, referred from 11 medical practices. INTERVENTION: Patients were asked to complete a survey and the Duke Anticoagulation Satisfaction Scale (DASS) before (at baseline) and after at least 3 months of STORM2 (at follow-up). MEASUREMENTS AND MAIN RESULTS: Patient satisfaction and time were assessed by survey and the DASS. Costs were measured from the patient's perspective. Overall 90% of responders preferred STORM2 to traditional clinic management. The DASS questions indicated that patients were more satisfied with their anticoagulation treatment and more likely to recommend oral anticoagulation to a friend after experiencing STORM2. In addition, patients found STORM2 to be less complicated and more convenient than traditional clinic management. For each traditional monthly visit, patients drove 20 miles and expended a total of 1.8 hours; using 55¢/mile for mileage reimbursement and $15/hour for lost wages, the cost for each visit was $38. The total cost for four STORM2 visits per month was $10, for a net savings of $28 per patient per month. A total of 76% of patients were willing to pay additional money to eliminate a monthly clinic visit. CONCLUSION: STORM2 is more convenient, less complicated, preferred by patients, and saves patients time and money compared with clinic management.