Rochester, MI—Renal function tends to decline over time in atrial fibrillation (AF) patients taking non–vitamin K oral anticoagulants, but the newer blood thinners appear to be associated with less kidney injury than warfarin, a new study finds.

The study, published in the Journal of the American College of Cardiology, is the latest in a series of investigations to confirm the real-world safety and efficacy of non–vitamin K antagonist oral anticoagulants (NOACs) versus warfarin.

“Our study demonstrated that renal function decline is very common among atrial fibrillation patients on blood thinners,” explained lead author Xiaoxi Yao, PhD, of the Mayo Clinic. “About 1 in 4 patients had significantly reduced kidney function within two years of being on any of these medications, and 1 in 7 patients had acute kidney injury.”

In light of the information, the study team sought to determine whether the type of blood thinner made a difference.

“In general, patients with atrial fibrillation taking blood-thinning medications tend to have declining kidney function over time,” noted senior author Peter Noseworthy, MD. “However, our findings indicate that the non-vitamin K antagonist oral anticoagulants as a group are associated with less injury to kidneys than warfarin.”

Used for the study were deidentified records of 9,769 patients from the OptumLabs Data Warehouse. All patients had been diagnosed with AF and initiated oral anticoagulants—apixaban, dabigatran, rivaroxaban, or warfarin—between October 1, 2010, and April 30, 2016.

Results indicate that the cumulative risk at the end of 2 years was:
• 24.4% for a decline in epidermal growth factor receptor (eGFR) of ≥30% 
• 4.0% for doubling of serum creatinine
• 14.8% for acute kidney injury (AKI)
• 1.7% for kidney failure

Overall, the three NOACs were associated with reduced risks of ≥30% decline in eGFR (hazard ratio [HR]: 0.77; 95% confidence interval [CI]: 0.66 to 0.89; P <.001), doubling of serum creatinine (HR: 0.62; 95% CI: 0.40 to 0.95; P = .03), and AKI (HR: 0.68; 95% CI: 0.58 to 0.81; P <.001) compared with warfarin. 

Individually, dabigatran was associated with lower risk of ≥30% decline in eGFR and AKI; rivaroxaban was associated with lower risks of ≥30% decline in eGFR, doubling of serum creatinine, and AKI, but apixaban did not have a statistically significant relationship with any renal outcomes, the researchers report.

“Renal function decline is common among patients with AF treated with oral anticoagulant agents,” study authors concluded. “NOACs, particularly dabigatran and rivaroxaban, may be associated with lower risks of adverse renal outcomes than warfarin.”

« Click here to return to Weekly News Update.