One of the reasons for the surge in popularity of the novel anticoagulant agents (dabigatran, apixaban and rivaroxaban) over the past few years has been the assurance of therapeutic anticoagulation. Warfarin users are not always within the therapeutic range, with some studies quoting subtherapeutic INRs in 30% of patients. This study in CHEST looks at the factors affecting the quality of anticoagulation control based on the AFFIRM study.
This group performed a linear regression analysis on the AFFIRM population and developed a score to look at independent predictors of time in the therapeutic range, as follows:
- Female sex
- Age < 60 years
- More than two comorbidities
- Treatment including interacting medication
- Tobacco use
They’ve put these into a little scoring system that helps predict poor INR control. Interestingly, compliance isn’t included here. A worthwhile read to keep in mind for your patients on warfarin.
Read it here.
source | CHEST
image | Pete