Maintenance of INR consistency during the initiation of warfarin

Background Safe anticoagulation management requires competent prescribers. Pharmacist-led anticoagulation clinics are effective, but data on specialist nurse-led services in the acute setting are scarce. Methods Twenty-eight ambulatory care patients who were referred to our medical day unit for warfarin commencement and stabilisation therapy were enrolled over two separate 1-month periods. One group of patients was treated by a trained nurse practitioner; the other group was treated by different caches of junior doctors. The patients were observed until their INR was stable enough for transfer to the pharmacist-led anticoagulation clinic. INR control in the two groups was compared. Findings There were a total of 195 INR measurements, and the mean number of INR measurements per patient was similar in both groups. The patients treated by the junior doctors were kept in the medical day unit for a longer period, but the mean INR over time in this group was more variable. Conversely, the patients treated by the nurse practitioner group had more consistency and less variation in INR measurements. Interpretation The better INR consistency and minimal variation reported for the nurse-practitioner group implies better control. If we assume that a poorly controlled INR poses a higher clinical risk, then the nurse practitioner dosing regime is a safer option. The current working patterns of junior doctors are not conducive to providing such continuity of care; therefore, in the ambulatory care setting, clinical risks may be reduced if anticoagulation is initiated and stabilised by a designated health-care practitioners with the required competencies and experience.