Patients' time in therapeutic range on warfarin among US patients with atrial fibrillation: Results from ORBIT-AF registry
Publication Date
2015
Journal Title
Am Heart J
Abstract
BACKGROUND: Time in therapeutic range (TTR) of international normalized ratio (INR) of 2.0 to 3.0 is important for the safety and effectiveness of warfarin anticoagulation. There are few data on TTR among patients with atrial fibrillation (AF) in community-based clinical practice. METHODS: Using the US Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF), we examined TTR (using a modified Rosendaal method) among 5,210 patients with AF on warfarin and treated at 155 sites. Patients were grouped into quartiles based on TTR data. Multivariable logistic regression modeling with generalized estimating equations was used to determine patient and provider factors associated with the lowest (worst) TTR. RESULTS: Overall, 59% of the measured INR values were between 2.0 and 3.0, with an overall mean and median TTR of 65% +/- 20% and 68% (interquartile range [IQR] 53%-79%). The median times below and above the therapeutic range were 17% (IQR 8%-29%) and 10% (IQR 3%-19%), respectively. Patients with renal dysfunction, advanced heart failure, frailty, prior valve surgery, and higher risk for bleeding (ATRIA score) or stroke (CHA2DS2-VASc score) had significantly lower TTR (P < .0001 for all). Patients treated at anticoagulation clinics had only slightly higher median TTR (69%) than those not (66%) (P < .0001). CONCLUSIONS: Among patients with AF in US clinical practices, TTR on warfarin is suboptimal, and those at highest predicted risks for stroke and bleeding were least likely to be in therapeutic range.
Volume Number
170
Issue Number
1
Pages
141-8, 148.e1
Document Type
Article
EPub Date
2015/06/22
Status
Faculty
Facility
School of Medicine
Primary Department
General Internal Medicine
PMID
DOI
10.1016/j.ahj.2015.03.017