Factors affecting quality of anticoagulation control amongst atrial fibrillation patients on warfarin:The SAMe-TT2R2 (Sex female, Age less than 60, Medical history, Treatment strategy [rhythm control], Tobacco use [doubled], Race [doubled] score

Chest Journal: May 9, 2013

Background  When oral anticoagulation (OAC) with adjusted dose Vitamin K antagonist (VKA,) is used, the quality of anticoagulation control (as reflected by time in therapeutic range (TTR) of the International Normalised Ratio, INR) is an important determinant of thromboembolism and bleeding. Our objective was to derive a validated scheme using patient-related clinical parameters for assessing the likelihood of poor INR control amongst atrial fibrillation (AF) patients on VKA therapy.

Methods  The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial population was randomly divided into derivation and internal validation cohorts using an 1:1 ratio. We used linear regression analysis to detect clinical factors associated with TTR and binary logistic regression to evaluate the predictive performance of a model incorporating these factors for different cut-off values of TTR. The derived model was externally validated in a cohort of anticoagulated patients prospectively recruited. Read more