Relation of the time in therapeutic range (TTR) of warfarin to bleeding incidences in patients with atrial fibrillation [Abstract]

Conference abstract;
Objectives: Warfarin use in atrial fibrillation has been established for preventing occurrence of stroke in patients with atrial fibrillation. However, safety and clinical monitoring of warfarin use is crucial due to its risk of bleeding complications. This study aims to compare and establish relation of time in therapeutic range (TTR) of warfarin in patients with atrial fibrillation in the first 6 months and 6 month thereafter of anticoagulation therapy.
Methods: This is a retrospective study carried out at a tertiary-care hospital with anticoagulation clinic in the state of Selangor, Malaysia. Data collected included patients’ demographics, co-morbidities, and international normalized ratio (INR). TTR were determined using Rosendaal method based on records found in database (INR Desk 4.0 system) and patients’ hemorrhage events were also recorded. Samples of the study were patient who started warfarin from January 2009 until March 2013.
Results: A total of 167 patients with atrial fibrillation were enrolled and only 6% (n=10) achieved TTR of more than 75% for the first 6 months of warfarin use as compared to 16.8% (n=28) of TTR more than 75% 6 months thereafter. As for bleeding incidences, 29% (n=45) of patients in the group of TTR less than 75% in the first 6 months had bleeding complications as compared to 18.7% (n=26) in patients of TTR less than 75% 6 months after.
Conclusions: A more regular follow up is necessary during the first 6 months of new warfarin users as they tend to be out of the TTR and have a higher bleeding risk.
Study site: anticoagulation clinic, tertiary hospital, Selangor, Malaysia