A Comparison of Warfarin Monitoring Service Models

Background: Warfarin-related knowledge and patient satisfaction with warfarin monitoring services are generally high with respect to anticoagulation-related care received. Providing a cost-effective warfarin monitoring service while improving warfarin-related knowledge, patient safety and satisfaction can be challenging. Objectives: To compare ‘post and dose’ service offered by the Calderdale Royal Hospital (CRH) and ‘face-to-face’ service offered by Huddersfield Royal Infirmary (HRI) in terms of costs of service delivery, patient satisfaction, warfarin-related knowledge and safety indicators. Methods: A cross-sectional sample of 160 patients on long-term warfarin therapy from anticoagulation (outpatient) clinics at CRH and HRI using interviewer-administered data collection form. International Normalized Ratio (INR), Time in Therapeutic Range (TTR) and Variance Growth Rate (VGR) values of last 12 months and the data on costs of service delivery, knowledge and satisfaction were collected. Results: Patients monitored at HRI had higher mean VGR value (0.35 ± 0.62 vs. 0.17 ± 0.17, p = 0.092) and slightly lower mean TTR (68.70 ± 19.43 vs. 69.63 ± 17.71, p = 0.756) compared with CRH patients. Patients monitored in ‘post and dose’ were estimated at a price of £11.06 per patient per visit and each patient in face-to-face service only cost £9.70 per visit. Patients monitored at HRI had marginally higher overall knowledge score (65.22 ± 23.29 vs. 60.31 ± 20.93, p = 0.165) and overall satisfaction score (15.59 ± 3.16 vs. 15.05 ± 3.10, p = 0.279) compared with CRH patients. A positive and significant correlation was found between patients’ knowledge and patient satisfaction (r = +0.327, p = 0.001). Conclusion: Although, HRI provided monitoring service at a slightly lower cost than CRH, patients monitored at CRH had better anticoagulation control and favourable indicators. Warfarin-related knowledge needs to be improved to achieve further improvement in quality of warfarin use.