Anticoagulation's benefits may outweigh risks for afib with chronic kidney disease

Anticoagulation therapy may have a greater benefit to patients with atrial fibrillation and chronic kidney disease than risk. However, balancing the two may be about finding the right course of treatment for the right duration.

Researchers led by Anders Nissen Bonde, MB, of the cardiology department at Copenhagen University Hospital Gentofte in Gentofte, Denmark, used data from Danish population databases. Patients with atrial fibrillation were stratified by CHA2DS2-VASc (Congestive heart failure; Hypertension; Age greater than or equal to 75 years; Diabetes mellitus; previous Stroke, transient ischemic attack, or thromboembolism; Vascular disease; Age 65 to 74 years; Sex category) and by degree of chronic kidney disease (non-end-stage, end-stage or renal replacement therapy).

Compared with patents with similar CHA2DS2-VASc scores without chronic kidney disease, patients with chronic kidney disease had a significantly increased risk for stroke. In all CHA2DS2-VASc categories, however, renal replacement therapy bore significantly higher risk: from a 5.5-fold higher risk in patients with scores of 0 to 1.6 higher risk among patients with a score of two or more.

Warfarin, however, seemed to mitigate some of those risks for patients with high CHA2DS2-VASc scores.

In patients with CHA2DS2-VASc scores of two or more on renal replacement therapy, taking warfarin lowered risk for all-cause death (hazard ratio: 0.85). Meanwhile, in patients with non-end-stage chronic kidney disease and high risk CHA2DS2-VASc scores, patients had a lower risk of fatal stroke and bleeding (hazard ratio: 0.71), cardiovascular death (hazard ratio: 0.8), and all-cause death (hazard ratio: 0.64) when taking warfarin.

The most benefit was seen for high-risk patients taking warfarin for no more or less than 30 days.

Bonde et al wrote that based on the effect seen in a real-world population, future efforts to define risks in these patients should include stratified chronic kidney disease as well as CHA2DS2-VASc.

As noted in an editorial by Timothy Ball, MD, from Baylor University Medical Center in Dallas, and colleagues, changing current prescribing practices may improve patient outcomes significantly following these findings. While the number of patients with CHA2DS2-VASc scores of two or more were high, less than a quarter of those without chronic kidney disease and less than 20 percent of those with end-stage chronic kidney disease were prescribed warfarin.

“This study provides powerful data about the role of anticoagulation in CKD [chronic kidney disease]; however, additional data are needed in CKD patients with AF [atrial fibrillation] to better understand the role of antiplatelet agents, warfarin, and the novel anticoagulants,” Ball et al wrote.

This study was published in the Dec. 16 issue of the Journal of the American College of Cardiology.