Author: Benjamin Steinberg
For the one percent of the population affected by atrial fibrillation, a form of irregular heartbeat, increased risk for blood clots and stroke is a serious concern. Medicines used to thin the blood offer a relatively simple treatment that can significantly reduce the risk of clots and strokes. A study of 5,738 atrial fibrillation patients, led by Benjamin A. Steinberg, M.D., M.H.S. at the University of Utah, examined whether patients that were prescribed non-vitamin K antagonist oral anticoagulants (NOACs), a specific kind of blood thinner, received proper dosing of their medicine and tracked their health outcomes over two years.
Steinberg and colleagues found that 13 percent of patients did not receive proper dosing of NOACs: 9.4 percent received lower than recommended doses, and 3.4 percent received a dose higher than the recommended amount. Patients receiving doses outside of the FDA-recommended amount had significantly worse clinical outcomes as well. Compared to patients receiving the appropriate dosage, the risk of death was nearly doubled in over-dosed patients, and under-dosed patients experienced increased rates of hospitalization due to cardiac events.
Statistical analyses suggested doctors may have prescribed off-label doses in an effort to accommodate factors such as patient age, sex, stroke risk, and risk of bleeding. However, the results from this study demonstrate that deviation from approved dosing regimens is associated with worse outcomes. This study offers a valuable perspective on the importance of closely following FDA dosing guidelines when prescribing NOACs to treat patients with atrial fibrillation.
It was accompanied by an editorial by colleagues in the School of Pharmacy at the University of Utah, Daniel M. Witt, PharmD, and Alisyn L. Hansen, PharmD.
-written by Meredith Hasenoehrl