Premium
Warfarin anticoagulation intensity in specialist‐based and in computer‐assisted dosing practice
Author(s) -
ONUNDARSON P. T.,
EINARSDOTTIR K. A.,
GUDMUNDSDOTTIR B. R.
Publication year - 2008
Publication title -
international journal of laboratory hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.705
H-Index - 55
eISSN - 1751-553X
pISSN - 1751-5521
DOI - 10.1111/j.1751-553x.2007.00976.x
Subject(s) - dosing , medicine , warfarin , atrial fibrillation , venous thromboembolism , clinical practice , cardiology , intensive care medicine , thrombosis , physical therapy
Summary The efficacy and safety of oral anticoagulation (OA) with vitamin K antagonists depends on maintaining anticoagulation intensity, measured as international normalized ratio (INR), within defined target ranges. We assessed the quality of our current software‐assisted warfarin dosing in the year 2006 in 941 unselected consecutive patients on stable OA with atrial fibrillation (AF), venous thromboembolism (VTE) and prosthetic heart valves (PHV) by comparing it to our previous cardiologist‐based dosing practice in 1992 when a study was carried out on 241 comparable patients. Over 14 years, the time within target range increased in all three anticoagulated groups, i.e. in AF patients from 46% to 81%, in VTE patients from 62% to 84% and in patients with PHV from 40% to 64%. Only 1% of the treatment time is now spent at INR < 1.5 compared to 7% previously ( P < 0.0001) and 0.4% of the treatment time at INR > 4.0 presently compared to 2.8% in the past ( P < 0.0001). INR‐targets are better achieved with the current software‐assisted dosing practice and extreme low and high values are less common than previously. The results provide indirect evidence suggesting that both efficacy and safety has improved with the current practice.