ACC 2019: Oral anticoagulants underused, aspirin overused to treat atrial fibrillation in patients with advanced chronic kidney disease

March 16, 2019 — Only approximately half of patients with chronic kidney disease and atrial fibrillation were treated with oral anticoagulants (OACs), and this proportion decreased significantly as kidney disease became more severe.

For patients with kidney disease and atrial fibrillation (AF), the approach to stroke prevention may be affected by how advanced their kidney disease is, according to new findings presented Saturday at the American College of Cardiology Scientific Sessions.

The DCRI’s Sean Pokorney, MD, MBA, who worked on the study team, said that many patients with atrial fibrillation are not treated with oral anticoagulation, which increases risk of stroke. The group was interested in examining how advanced kidney disease affects this under-treatment, as well as how different treatment options affect patient outcomes.

The study included about 300,000 patients with atrial fibrillation and chronic kidney disease from the Premier Healthcare Database, which represents 20 percent of hospital discharges across the U.S. The dataset spanned from 2011 to 2015.

The team examined four patient groups: those treated with warfarin (the conventional OAC), those treated with newer direct oral anticoagulants (DOACs), those treated with aspirin only, and those who received no OAC or aspirin. Results showed that as kidney disease advanced, OAC treatment rates decreased while aspirin treatment rates increased. Likelihood of treatment with a DOAC dropped significantly in the later stages of kidney disease, while warfarin treatment rates remained relatively stable.

“The main way we can intervene here is to address the overuse of aspirin,” Pokorney said. “There is a misconception that aspirin is safer than OACs and still provides some stroke protection, but we believe there is actually minimal protection against atrial fibrillation related strokes provided by aspirin and that it is not any safer than newer OAC options. The trends we found are concerning because by overusing aspirin, we are still exposing patients to risk of bleeding without the benefits of stroke prevention from an OAC.”

The group also examined patient outcomes after one year. Treatment with DOACs resulted in a lower 1-year mortality rate than treatment with warfarin across all stages of kidney disease. In Stages I through III, mortality in the DOAC group was 4.4 percent, as compared to 5 percent in the warfarin group. In patients with stage IV, V, or end-stage renal disease, 6.3 percent of those treated with DOACs experienced mortality versus 8.1 percent of those treated with warfarin.

Pokorney said that providers are appropriately hesitant to prescribe DOACs to patients with end-stage renal disease because of limited data on safety in this patient population. Along with the DCRI’s Christopher Granger, MD, he is working on RENAL-AF, an ongoing DCRI study that is randomizing hemodialysis patients with atrial fibrillation to either apixaban (a DOAC) or warfarin. This study’s results could provide further evidence for DOAC safety in chronic kidney disease patients, he said.

The DCRI’s Kevin Thomas, MD; Kevin Anstrom, PhD; and Christopher Granger, MD, also contributed to the study presented Saturday. Janssen Pharmaceuticals provided funding for the study.