Risk of stroke and oral anticoagulant use in atrial fibrillation: a cross-sectional survey

Abstract

BackgroundOral anticoagulants substantially reduce the risk of stroke in atrial fibrillation but are underutilised in current practice. AimTo measure the distribution of stroke risk in patients with atrial fibrillation (using the CHADS 2 and CHA 2 DS 2 -VASc scores) and changes in oral anticoagulant use during 2007-2010. Design and settingLongitudinal series of cross-sectional survey in 583 UK practices linked to the QResearch ® database providing 99 351 anonymised electronic records from people with atrial fibrillation. MethodThe proportion of patients in each CHADS 2 and CHA 2 DS 2 -VASc risk band in 2010 was calculated; for each of the years 2007-2010, the proportions with risk scores ≥2 that were using anticoagulants or antiplatelet agents were estimated. The proportions identified at high risk were re-estimated using alternative definitions of hypertension based on coded data. Finally, the prevalence of comorbid conditions in treated and untreated high-risk (CHADS 2 ≥2) groups was derived. ResultsThe proportion at high risk of stroke in 2010 was 56.9% according to the CHADS 2 ≥2 threshold, and 84.5% according to CHA 2 DS 2 -VASc ≥2 threshold. The proportions of these groups receiving anticoagulants were 53.0% and 50.7% respectively and increased during 2007-2010. The means of identifying the population of individuals with hypertension significantly influenced the estimated proportion at high risk. Comorbid conditions associated with avoidance of anticoagulants included history of falls, use of nonsteroidal anti-inflammatory drugs, and dementia. ConclusionOral anticoagulant use in atrial fibrillation has increased in UK practice since 2007, but remains suboptimal. Improved coding of hypertension is required to support systematic identification of individuals at high risk of stroke and could be assisted by practice-based software.

Optimising stroke prevention in patients with atrial fibrillation: application of the GRASP-AF audit tool in a UK general practice cohort

“…The present finding of the under-utilisation of OAC in patients with AF at moderatehigh risk of stroke is corroborated by other recent prospective observational cohorts 5,6,10,17 and a systematic review. 9 The GARFIELD registry, which also assessed stroke risk using the CHA 2 DS 2 -VASc score, found that two out of five patients with a CHA 2 DS 2 -VASc score ≥2 did not receive OAC.…”

“…[1][2][3] Until recently, the only OAC available was an 'inconvenient' drug, warfarin; thus, older guidelines had focused on identifying 'high risk' patients for warfarin, using risk scores such as the CHADS 2 score. 4 Given the limitations and difficulties associated with warfarin, there was substantial undertreatment with OAC, [5][6][7][8][9][10] and many patients were treated with aspirin, despite this drug being minimally effective and conferring a risk of bleeding similar to warfarin. 11,12 In the UK, a survey of 1857 UK general practices using the Guidance on Risk Assessment and Stroke Prevention in Atrial Fibrillation (GRASP-AF) audit tool reported that 34% of patients with a CHADS 2 score ≥2 did not receive OAC therapy.…”

Untreated atrial fibrillation in the United Kingdom: Understanding the barriers and treatment options

“…Overall, this study suggested that less than half (49.3%) of patients with a history of AF received an anticoagulant and that anticoagulant uptake increases through CHADS 2 score 0-3 and thereafter reaches a plateau [16]. These results are similar to those of another recent study [12] and represent an improvement compared to what had previously been described [32]. Nevertheless, if the treatment threshold for anticoagulation is a CHADS 2 score P1, this would include 84% of the AF population, which is significantly higher than the percentage of patients currently given anticoagulation.…”

“…Despite the fact that oral anticoagulation is effective in preventing strokes due to AF, there is extensive evidence suggesting that this therapy remains underused [7,[11][12][13][14]. In fact, although current guidelines clearly define indications for anticoagulation treatment and its vast impact in the prevention of stroke, barriers to the implementation of oral anticoagulation continue to exist among physicians and patients.…”

Optimizing the use of oral anticoagulant therapy for atrial fibrilation in primary care: a pharmacist-led intervention

“…Despite this plethora of evidence, it has been shown consistently that patient management in terms of the use of anticoagulants is suboptimal [20][21][22][23]. There is, however, a paucity of published literature describing approaches that have been adopted to address this shortfall.…”