Novel oral anticoagulant use after stroke is increasing but still lags behind warfarin

Despite the approval of novel oral anticoagulants in recent years, nearly 90 percent of atrial fibrillation patients with ischemic stroke or transient ischemic attack (TIA) receive warfarin, according to analysis of patients hospitalized between October 2010 and September 2012.

At discharge, 88.9 percent of patients were prescribed warfarin compared with 9.6 percent for dabigatran (Pradaxa, Boehringer Ingelheim) and 1.5 percent for rivaroxaban (Xarelto, Bayer/Johnson & Johnson). Still, prescriptions for novel oral anticoagulants significantly increased during the time period in this group of high-risk patients.

Priyesh A. Patel, MD, of the Duke Clinical Research Institute in Durham, N.C., and colleagues published their findings online in Circulation: Cardiovascular Quality and Outcomes on June 9.

More than 2.5 million people in the U.S. have atrial fibrillation. If patients have thromboembolic events, they are commonly prescribed warfarin, which Patel et al mentioned reduces the risk of anticoagulation by approximately 66 percent. However, warfarin is associated with food and drug interactions, and patients taking the drug need to be regularly monitored.

The newer anticoagulants include dabigatran, rivaroxaban and apixaban (Eliquis, Bristol-Myers Squibb), all have been found to be at least noninferior to warfarin for thromboembolic prophylaxis, according to the researchers. Patel et al mentioned the drugs also require less monitoring than warfarin and are cost-effective in high-risk populations.

They analyzed the Get With The Guidelines-Stroke registry that includes data from more than 1,800 hospitals. They evaluated 61,655 patients with atrial fibrillation who were hospitalized for ischemic stroke or TIA and received warfarin, dabigatran or rivaroxaban when discharged between Oct. 19, 2010 and Sept. 27, 2012. Apixaban had not been approved as of the end of the study. Of the patients, 79.1 percent had ischemic stroke, while 20.9 percent had TIA.

The median age was 77 for patients receiving a novel oral anticoagulant and 79 for patients receiving warfarin, while 51.8 percent and 53.3 percent of patients in the respective groups were women.

During the early time period in the study, few patients received the new anticoagulants because dabigatran was not FDA-approved until the fourth quarter of 2010 and rivaroxaban was not approved until the third quarter of 2011.

By the end of the study, 16 percent to 17 percent of the patients were prescribed the new anticoagulants. In addition, from the first quarter of 2011 to the second quarter of 2012, the proportion of patients receiving warfarin or nonwarfarin/non-novel oral anticoagulants declined from 93.4 percent to 77.1 percent. During the same time period, the proportion of patients who were not anticoagulated at hospital discharge decreased from 6.3 percent to 5.9 percent.

The researchers wrote that the novel oral anticoagulants were typically prescribed for patients with lower stroke risk and better functional status, although their use varied widely among hospitals.

Limitations of the study included that it analyzed a voluntary quality improvement program that may not represent the general hospital population. Patel et al noted that hospitals in the study were more likely to be teaching hospitals, were less likely to be rural and were larger than the typical U.S. hospital. They also could not evaluate adherence rates after patients were discharged.