Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major predisposing risk factor for stroke. Current UK guidelines propose stroke-risk stratification of AF patients. Anticoagulation with warfarin is recommended for high risk patients, whereas treatment with aspirin alone is advised for those at low risk. The aim of this audit was to review practice at our institution and ascertain if guidelines on AF treatment were being followed.

A retrospective review of all patients diagnosed with non-valvular AF in June 2010 was undertaken. Patient records were reviewed to collect demographic and co-morbidity data relevant to stroke risk stratification. This was subsequently used to stratify patients according to stroke-risk using the CHADS2 scoring system. The use of anticoagulation and anti-platelet medication as well as any documented reasons for the omission of anticoagulation in high risk patients was noted.

The prevalence of non-valvular AF in our practice population was 1.5% (151/10,155); 70% (105/151) of AF patients were found to be at high risk of stroke; 36% (38/105) of high risk patients were not on anticoagulation and the majority (58%) of these patients had no clear reason documented for the omission of warfarin. Of the 15 patients at low risk of stroke, 12 (80%) were on warfarin. Seven (4.4%) of the 151 AF patients were on both warfarin and aspirin and six (4%) were on neither medication. The commonest documented reasons for omission of warfarin in the high risk group were dementia and a history of gastrointestinal bleeding.

The lack of documentation on withholding a proven beneficial treatment in high risk patients could potentially leave physicians open to medico-legal scrutiny. Maintaining low risk patients on anticoagulation may expose them to unnecessary risk. We recommend the use of automated audit tools designed to improve compliance with national guidelines.