Comparative effectiveness of general practitioner versus pharmacist dosing of patients requiring anticoagulation in the community

Objective: To compare pharmacist- with general practitioner-managed anticoagulation in the community. Design: Included in the study were all patients who had been managed by general practitioners (GPs) and subsequently referred to the pharmacist-led outreach service within Gateshead & South Tyneside Health Authority. A retrospective analysis was carried out recording individual international normalized ratio (INR) estimations, the time interval between successive tests and whether the result resided within the prescribed therapeutic range. These values were derived for both the GP- and pharmacist-managed elements of care. Subjects: Fifty-one patients who met the inclusion criteria identified from eight practices had been successively treated by GPs and then by pharmacists. Eighteen patients (35.3%) had a diagnosis of non-rheumatic atrial fibrillation, 10 (19.6%) had thromboembolic disease and 13 (25.5%) had valvular disease. Results: In total, 1782 INR results were analysed. GPs were responsible for 1075 (60.3%) of these estimations and pharmacists for the remaining 707 (39.7%). Of the GP-monitored results the patient-mean proportion of estimates that resided within the prescribed therapeutic range was 0.6 (SD = 0.21, n = 51) compared with pharmacist management where patients showed a mean in range proportion of 0.7 (SD = 0.18, n = 51, P = 0.03). The mean inter-test interval was 28.6 days (SD = 8.65, n = 51) for GPs compared with 34.1 days (SD = 12.3, n = 51, P = 0.01) for pharmacists. The weighted INR index for GPs was 17.2 (SD = 7.93, n = 51) compared with 24.7 (SD = 13.15, n = 51, P < 0.001) for pharmacists. Conclusions: There is no apparent detriment to INR control when pharmacist management is compared with that of GPs. The overall proportion of INR estimations within the prescribed range is greater for pharmacists than for GPs and the interval between tests is longer for pharmacists compared with GPs.