June 22, 2013The American Journal of CardiologyOpen Access

Impact of Co-morbidities and Patient Characteristics on International Normalized Ratio Control Over Time in Patients With Nonvalvular Atrial Fibrillation

View Full Paper

Ask AI

Bookmark

Why the study?

Are comorbidities such as heart failure, diabetes, and stroke associated with lower time in therapeutic range (TTR) in patients with nonvalvular atrial fibrillation on warfarin?

Structured PICO

Are comorbidities such as heart failure, diabetes, and stroke associated with lower time in therapeutic range (TTR) in patients with nonvalvular atrial fibrillation on warfarin?

Population

23,425 adult patients with nonvalvular atrial fibrillation who used warfarin for a 12-month period with no gap of >60 days between visits, mean age 74.8, 84.8% aged ≥65 years.

Intervention

Presence of comorbidities (heart failure, diabetes, previous stroke) or higher CHADS₂ score (≥2)

Comparator

Absence of these comorbidities or lower CHADS₂ score

Outcome

Lower time in therapeutic range (TTR <55%)surrogate

Patients with nonvalvular atrial fibrillation and comorbidities such as heart failure, diabetes, or prior stroke have poorer anticoagulation control on warfarin, highlighting the need for closer monitoring or alternative therapies in these high-risk groups.

Implication

May warrant closer TTR monitoring in comorbid AF on warfarin; leaves open optimal strategies and NOAC impact.

Abstract

This study determined the association between co-morbidities, including heart failure (HF) and time in therapeutic range (TTR), in patients with nonvalvular atrial fibrillation. Longitudinal patient-level anticoagulation management records collected from 2006 to 2010 were analyzed. Adult patients with nonvalvular atrial fibrillation who used warfarin for a 12-month period with no gap of >60 days between visits were identified. TTR <55% was defined as "lower" TTR. CHADS₂ score of ≥2 was defined as "higher" CHADS₂. Logistic regression analyses were conducted to determine the association between co-morbidities and TTR. A total of 23,425 patients met the study criteria. The mean age ± SD was 74.8 ± 9.7 years, with 84.8% aged ≥65 years. The most common co-morbidities were hypertension (41.7%), diabetes (24.1%), HF (11.7%), and previous stroke (11.1%). The mean TTR ± SD was 67.3 ± 14.4%, with 18.6% of patients in the lower TTR range. In multivariate analyses using age, gender, hypertension, diabetes, stroke, and region as covariates, HF (adjusted odds ratio [OR] 1.41, 95% confidence interval [CI] 1.28 to 1.56; p <0.001), diabetes (OR 1.28, 95% CI 1.19 to 1.38; p <0.001), and previous stroke (OR 1.15, 95% CI 1.04 to 1.27; p <0.001) were associated with lower TTR. In a second set of multivariate analyses using gender and region as covariates, a higher CHADS₂ score was associated with lower TTR (OR 1.11, 95% CI 1.04 to 1.18; p <0.001). In conclusion, HF was associated with the greatest likelihood of a lower TTR, followed by diabetes, then stroke. Anticoagulation control may be more challenging for patients with these conditions.