January 8, 2014 – The DCRI’s Benjamin Steinberg, MD, and his colleagues sought to determine usage and dosage patterns among atrial fibrillation patients.
Atrial fibrillation (AF) patients who receive the new oral anticoagulant dabigatran tend to be younger and are at lower risk of bleeding and stroke, according to a new study by DCRI researchers.
The study was conducted by the DCRI’s Benjamin Steinberg, MD (pictured); DaJuanicia Holmes, MS; Jonathan Piccini, MD, MHS; Laine Thomas, PhD; and Eric Peterson, MD, MPH. It appears in the December 2013 issue of the Journal of the American Heart Association.
Atrial fibrillation is known to increase the risk of stroke or systemic embolism by a significant amount. Clinicians have traditionally used warfarin to reduce this risk; however, warfarin has a number of shortcomings, including a narrow therapeutic window, need for frequent monitoring, and numerous drug and food interactions. Recent studies have indicated that dabigatran is as effective as warfarin but does not have the same limitations. To date, however, there has been little research into usage and dosage patterns among dabigatran users in the United States.
In this study, the researchers analyzed patient data obtained from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT‐AF), a nationwide registry of outpatients with AF treated by primary care physicians, cardiologists, and/or electrophysiologists. The researchers examined data from patients who were enrolled in the registry between June 2010 and August 2011 and followed for 12 months. Of the 9974 AF patients included in this sample, 1217 (12 percent) were treated with dabigatran.
Overall, patients receiving dabigatran were younger (with a median age of 72 versus 75 years), more likely to be white (92 percent versus 89 percent), more likely to have private insurance (33 percent versus 25 percent), and less likely to have prior cardiovascular disease (4 percent versus 33 percent). They had more new‐onset AF (8.8 percent versus 4.1 percent), lower CHADS2 scores (mean 2.0 versus 2.3), and lower Anticoagulation and Risk Factors in Atrial Fibrillation scores (mean 2.4 versus 2.8). More than half (56 percent) of patients with severe kidney disease were not prescribed reduced dosing, whereas 10 percent (n=91/920) with preserved renal function received lower dosing.
These patterns, the researchers concluded, suggest that many clinicians have embraced a conservative adoption strategy (prescribing the drug to patients at lower risk for adverse events) despite dabigatran’s demonstrated benefits to AF patients relative to warfarin. As more doctors become familiar with the drug, they may be more likely to prescribe it to more of their patients.