Use of oral anticoagulation to prevent stroke in patients with atrial fibrillation (AFib) varies substantially by region, according to results of a new study published June 27 in Stroke. This variation presented a similar geographic pattern to variation in stroke rates.

Researchers used claims data from a 5 percent random sample of Medicare beneficiaries to identify newly diagnosed AFib patients who were prescribed novel oral anticoagulants (NOACs) (n = 8,659), warfarin (n = 11,771) or no oral anticoagulation therapy (n = 18,226) from 2013 to 2014. From there, each patient was assigned to one of the 306 Dartmouth hospital-referral regions based on his/her zip code.

Overall results showed large geographic variation in the use of oral anticoagulation in stroke prevention, with patients in the Midwest (0.54) and Northeast (0.54) having the greatest likelihood of any oral anticoagulation being initiated. Patients in the South had the lowest likelihood (0.47). The mean adjusted probability of initiating oral anticoagulation was 0.51, ranging from 0.32 to 0.72. Researchers noted that "anticoagulation use was lowest in Texas, Oklahoma, Missouri, Arkansas, Mississippi, and North Carolina, all of which are well known for having unusually high rates of stroke."

Also of note, data showed patients on oral anticoagulation were less likely to be prescribed NOACs in regions with higher anticoagulation use than in regions with less anticoagulant use (correlation coefficient, −0.16;p = 0.006).

Specifically, the mean adjusted probability of a NOAC being prescribed among those on oral anticoagulation was 0.42 and was highest in the South (0.50) and lowest in the Midwest (0.36) and Northeast (0.39).

"Because oral anticoagulation use was lowest in regions with the highest stroke incidence rates, the implementation of interventions targeted at increasing the use of oral anticoagulation in AFib could have high potential to decrease the incidence of stroke in these areas," researchers said. "In future studies, it will be important to analyze whether the unusually high rates of stroke in the stroke belt are partially attributed to the underuse of oral anticoagulation in this region."

Keywords: Warfarin, Atrial Fibrillation, Incidence, North Carolina, Mississippi, Arkansas, Oklahoma, Missouri, Texas, Anticoagulants, Stroke, Cytarabine, Medicare, Referral and Consultation

< Back to Listings