Associations between anticoagulation therapy and risks of mortality and readmission among patients with heart failure and atrial fibrillation.

Hernandez AF1, Liang L2, Fonarow GC2, Hammill BG2, Hammill SC2, Heidenreich PA2, Masoudi FA2, Qualls LG2, Al-Khatib SM2, Piccini JP2, Curtis LH2.

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Abstract

BACKGROUND:

Patients with heart failure and atrial fibrillation are at higher risk of thromboembolic events than patients with heart failure alone. Yet, the use of anticoagulation therapy varies in clinical practice, especially among older patients, for whom its effectiveness is poorly understood.

METHODS AND RESULTS:

Using clinical registry data linked to Medicare claims from 2005 to 2011, we examined outcomes of older patients hospitalized with heart failure and atrial fibrillation who newly initiated anticoagulation therapy at discharge. We used Cox proportional hazards models and inverse probability-weighted treatment estimates to adjust for selection bias. Main outcomes were mortality and readmission at 1 and 3 years. Among 5105 patients in 195 hospitals, 1623 (31.8%) started anticoagulation therapy at discharge. Treated patients had lower unadjusted rates of all-cause mortality (26.4% versus 42.8%; P<0.001) and all-cause readmission (58.4% versus 63.7%; P<0.001) at 1 year. After inverse weighting for the probability of treatment and adjustment for other discharge medications, anticoagulation therapy was associated with significantly lower 1-year mortality (hazard ratio, 0.70; 99% confidence interval, 0.59-0.82), but there was no statistically significant difference in the risk of all-cause readmission (hazard ratio, 0.89; 99% confidence interval, 0.78-1.01) or other readmission outcomes. Results were similar at 3 years.

CONCLUSIONS:

Initiation of anticoagulation therapy at hospital discharge was associated with improved mortality at 1 and 3 years but was not associated with improved cardiovascular readmission among older patients with heart failure and atrial fibrillation.