Physician practices regarding contraindications to oral anticoagulation in atrial fibrillation: findings from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry

Abstract

Background: Oral anticoagulation (OAC) therapy reduces the risk of thromboembolic events associated with atrial fibrillation (AF), yet a substantial proportion of patients with AF are not prescribed OAC. The aim of this study is to describe the frequencies of and factors associated with OAC contraindications in contemporary clinical practice.

Methods: We analyzed data from the ORBIT-AF study, a national, prospective, outpatient registry of incident and prevalent AF. Oral anticoagulation contraindications were uniformly collected at enrollment by site personnel using a predefined list. Baseline patient and provider characteristics were compared between participants with and without documented OAC contraindications.

Results: From June 2010 to August 2011, 10,130 patients 18 years or older with electrocardiographically documented AF were enrolled at 176 practices. Of these, 1,330 (13.1%) had contraindications documented at the baseline visit: prior bleed (27.7%), patient refusal/preference (27.5%), high bleeding risk (18.0%), frequent falls/frailty (17.6%), need for dual antiplatelet therapy (10.4%), unable to adhere/monitor warfarin (6.0%), comorbid illness (5.3%), prior intracranial hemorrhage (5.0%), allergy (2.4%), occupational risk (0.8%), pregnancy (0.2%), and other (12.6%). Among patients with reported contraindications, 30.3% were taking warfarin or dabigatran, as compared with 83.0% of those without reported contraindications. Besides "patient refusal/preference," being labeled as having frequent falls or being frail was associated with the lowest OAC use among patients with high stroke risk.

Conclusions: Contraindications to OAC therapy among patients with AF are common but subjective. Many patients with reported contraindications were receiving OAC, suggesting that the perceived benefit outweighed the potential harm posed by the relative contraindication.