Burden of atrial fibrillation: a retrospective review of patients presenting to acute medical services

Abstract

Background: Atrial fibrillation (AF) is a major risk factor for stroke and is associated with increased stroke severity and greater morbidity and mortality. Anticoagulation is highly effective for preventing episodes of thromboembolism but remains under-utilised.

Aims: The aim of this review was to estimate the short-term risk of thromboembolic events in patients presenting with an acute medical illness, to assess rates of anticoagulation in eligible patients with AF and to describe physician decisions when prescribing anticoagulation in a hospital setting.

Methods: A retrospective cohort analysis of patients with AF presenting to acute medical services at Wellington Regional Hospital between 1 January 2012 and 31 December 2012 was performed.

Results: A total of 751 patient presentations with AF was identified; 613 unique patient encounters were eligible for analysis, and 38.8% of patients with a CHA₂ DS₂ -VASc score ≥2 were discharged after anticoagulation. The mean CHA₂ DS₂ -VASc score was 4.03 (SD = 1.94). The CHA₂ DS₂ -VASc score was not associated with being started on anticoagulation, odds ratio 1.16 (95% confidence interval = 0.83-1.61), P = 0.38, but age by decade older was associated with a reduced likelihood of being started on anticoagulation, odds ratio 0.61 (95% confidence interval = 0.41-0.89), P = 0.01. In untreated patients with a CHA₂ DS₂ -VASc score ≥2, the most frequently documented reasons not to initiate anticoagulation were decision deferred to the primary care physician, 15.6%; fall risk or frailty, 7.2%; and high bleeding risk, 6.6%. However, no reason was documented in 56.9%. The thromboembolic rate in patients discharged without anticoagulation within 3 months of presentation to acute medical services was 7/330 (2.1%).

Conclusion: Anticoagulation for stroke prevention in AF remains under-utilised in eligible patients presenting to acute medical services at a tertiary-level hospital.

Keywords: anticoagulation; atrial fibrillation; ischaemic stroke; thromboembolism.