Comparison of warfarin time in the therapeutic range at a pharmacist-run anticoagulation clinic and the RE-LY trial

Purpose. An audit was conducted to determine if the benefits of dabigatran treatment, as demonstrated in the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial, are applicable to patients with nonvalvular atrial fibrillation managed by a pharmacist-run anticoagulation clinic (PAC). Methods. The records of warfarin-treated patients managed by a PAC program over a three-year period were screened to identify patients with diagnosed nonvalvular atrial fibrillation and a goal International Normalized Ratio (INR) of 2-3; the case selection criteria were similar to those used in the RE-LY trial. Abstracted data included dates and results of INR monitoring and information needed to calculate CHADS(2) (Congestive Heart Failure, Hypertension, Age, Diabetes, and Stroke [doubled]) scores. Warfarin time in the therapeutic range (TTR) was the primary endpoint. A pairwise comparison of TTR distributions in subsets of patients grouped by CHADS(2) score was performed to test the hypothesis that any two groups had identical distributions. Results. Data on 314 PAC patients, including 9772 INR values, were analyzed. The mean S.D. TTR was 62.4% 24.5% (median, 66.7%), which was similar to the mean TTR reported in the RE-LY trial (p = 0.092). The distribution of TTR values in the PAC population differed significantly in patients with a CHADS(2) score of 2 versus a score of 3 (p = 0.0333 for Kuiper test), but no other significant differences were noted. Conclusion. TTR values among PAC-managed patients with nonvalvular atrial fibrillation were comparable to those reported in the RE-LY trial.