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SPLTRAK Abstract Submission
Effect of Polypharmacy on Time in Therapeutic Range of Warfarin Therapy in Patients with Nonvalvular Atrial Fibrillation
Shaban Mohammed1,4, Mohamed Kasem1, Amer Aljundi1, Mohammed Alhashemi2, Ayman El-Menyar3,5, Osama Abd El Samad1, Moza Al Hail1, Nidal Asaad2
1Pharmacy Department , Hamad Medical Corporation, Doha , Qatar/2Heart Hospital,Hamad Medical Corporation, Doha, Qatar/32Department of Clinical Medicine, Weill Cornel Medical College, Doha, Qatar/4American University of Barbados School of Medicine, Barbados, Barbados, Barbados/53Department of Surgery, Clinical Research, Hamad Medical Corporation, Doha, Qatar

Background: It has been shown that polypharmacy affects compliance to medications but its effect on anticoagulation control in patients prescribed warfarin is unclear. Objective: We sought to investigate the effect of polypharmacy on quality of anticoagulation control as measured by time in therapeutic range (TTR) in patients with nonvalvular atrial fibrillation (AF) treated with warfarin. Methods: We conducted a retrospective observational study for patients with nonvalvular AF treated with warfarin > 6 months at a tertiary cardiac care hospital in Qatar. Patient who had polypharmacy (defined as ≥ 6 medications) were compared with those who had no polypharmacy in terms of TTR. Results:  Of the 241 patients evaluated, 47.3% were in the polypharmacy arm. The two groups were similar in terms of gender, warfarin dose, and number of clinic visits.The mean TTR was 72.6 ± 14% in non-polypharmacy group and 67 ± 17% in polypharmacy (P = 0.006) subjects despite the higher prevalence of co-morbidities in the earlier group: heart failure (51.2 versus 28.1%, P = 0.001), diabetes mellitus (47.2 versus 27.2%, P = 0.001), and hyperlipidemia (65.4 versus 39.5%, P = 0.001) and older age (65 ± 11.3 versus 61.8 ± 13.5, P = 0.04) with subsequent higher CHADS2 score (2.4 ± 0.7 versus 1.9 ± 0.6, P = 0.001). Patients in both groups had similar major bleeding rates (1.6% in non-polypharmacy group vs. 1.8% in the polypharmacy group, p = 0.91). Conclusions: Our analysis revealed that polypharmacy had negative impact on TTR.Good-quality management of oral anticoagulation through optimizing TTR is achievable with minimizing polypharmacy and without increasing bleeding complications.   Key words: Anticoagulation; warfarin; time in therapeutic range; polypharmacy