Stroke and Bleeding in Afib with CKD

Posted by Sara Fazio • August 17th, 2012

In a study of data from Danish national registries, CKD was associated with an increased risk of stroke and bleeding among patients with atrial fibrillation. Warfarin decreased the risk of stroke among such patients. Both warfarin and aspirin increased the risk of bleeding.

The prevalence of both atrial fibrillation and chronic kidney disease increases with age. The prevalence of atrial fibrillation is 2.3% among persons 40 years of age or older and 5.9% among those 65 years of age or older, and the prevalence of end-stage renal disease increases from approximately 3.5% among persons 45 to 64 years of age to nearly 6% among those 75 years of age or older. Many patients have both disorders, and the number of such patients is increasing, owing in part to the aging population and the improved survival in both diseases.

Clinical Pearls

What is the effect of chronic kidney disease on the risk of stroke?

The U.S.-based Renal Data System has reported that chronic kidney disease increases the risk of stroke by a factor of 3.7, and end-stage renal disease (i.e., disease requiring renal-replacement therapy) increases the risk by a factor of 5.8. Atrial fibrillation increases the risk of stroke by a factor of 5, and chronic kidney disease increases the risk of stroke among patients without atrial fibrillation.

What is a CHA2DS2-VASc score?

This study evaluated the risk of stroke or systemic thromboembolism, with adjustment for CHA2DS2-VASc risk factors. The CHA2DS2-VASc score extends the CHADS2 algorithm to include additional nonmajor risk factors for stroke, including vascular disease (V), age between 65 to 74 years (A), and female gender (sex category or Sc).

Morning Report Questions

Q: What were the results of this study of patients with atrial fibrillation and chronic kidney disease with respect to risk of stroke or systemic embolism?

A: This study demonstrated that warfarin treatment was associated with a significantly decreased risk of stroke or systemic thromboembolism overall and among patients requiring renal-replacement therapy, and with a nonsignificantly decreased risk among patients with non-end-stage chronic kidney disease. In an analysis that compared     all patients who had any renal disease with those who had no renal disease, warfarin decreased the risk of stroke or systemic thromboembolism (hazard ratio, 0.76; 95% CI, 0.64 to 0.91; P=0.003), as did warfarin plus aspirin (hazard ratio, 0.74; 95% CI, 0.56 to 0.98; P=0.04). Aspirin was associated with an increased risk of stroke or systemic thromboembolism overall and among patients who had any renal disease, as compared with those who had no renal disease (hazard ratio, 1.17; 95% CI, 1.01 to 1.35; P=0.04).

Table 3. Hazard Ratios for Stroke or Systemic Thromboembolism.

Q: How did the risk of bleeding differ among patients with and without kidney disease?

A: The risk of bleeding was higher among patients with non-end-stage chronic kidney disease and among patients requiring renal-replacement therapy as compared to patients without renal disease, and treatment with warfarin, aspirin, or both incrementally increased this risk. Among all patients who had any renal disease, as compared with those who had no renal disease, there was an increased risk of bleeding with warfarin (hazard ratio, 1.33; 95% CI, 1.16 to 1.53; P<0.001), aspirin (hazard ratio, 1.17; 95% CI, 1.02 to 1.34; P=0.03), and warfarin plus aspirin (hazard ratio, 1.61; 95% CI, 1.32 to 1.96; P<0.001). Among patients with non-end-stage chronic kidney disease, the risk of bleeding increased with a higher dose of loop diuretics. The risk of bleeding was highest among patients with chronic glomerulonephritis and lowest among those with chronic tubulointerstitial nephropathy.

Table 4. Hazard Ratios for Bleeding.

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