CKD may raise stroke, bleeding risk in AF patients

Aug 22 2012

By Lauretta Ihonor, medwireNews Reporter

Danish study results show that the presence of chronic kidney disease (CKD) appears to raise the risk for stroke, systemic thromboembolism, and bleeding among patients with atrial fibrillation (AF).

And the risk for these three complications may also be influenced by the type of antithrombotic agent used to treat AF patients, say the authors.

Specifically, compared with no antithrombotic treatment, warfarin therapy was found to lower the risk for stroke and systemic thromboembolism among AF patients (independent of CKD status) by 41%, whereas aspirin therapy was found to increase this risk by 11%.

Both warfarin- and aspirin-only therapy raised the risk for bleeding by 28% and 21%, respectively.

"Thus, the net clinical effect of warfarin treatment requires careful assessment in patients with CKD," say the authors in The New England Journal of Medicine.

They add: "The data [obtained in this study] do not provide clear guidance regarding indications for anticoagulant therapy in patients with both AF and CKD."

The results arise from the analysis of 132,372 Danish AF patients, of whom 4488 had CKD.

Among those with CKD, 3587 had non-end-stage CKD and 901 had end-stage CKD, defined as CKD requiring renal-replacement therapy.

The risk for stroke or systemic thromboembolism was found to be a significant 49% and 83% higher among AF patients with non-end-stage and end-stage CKD, respectively, compared with CKD-free AF patients.

Jonas Olesen (Copenhagen University Hospital Gentofte) and co-authors report that in patients with non-end-stage CKD, this risk for stroke or systemic thromboembolism was independent of CKD severity, as determined by the intensity of treatment with loop diuretics.

The authors highlight several study design flaws that may have introduced some degree of bias into the findings obtained. For example, aspirin is available over the counter in Denmark, and as such, some patients categorized as receiving warfarin only may have also been self-medicating with aspirin.

Olesen et al therefore conclude that further investigation into the effects of different antithrombotic regimens on stroke, thromboembolism, and bleeding risk is required.

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