The role of contraindications in prescribing anticoagulants to patients with atrial fibrillation: a cross-sectional analysis of primary care data in the UK

Nicola Adderley, Ronan Ryan, Tom Marshall

Underuse of anticoagulants in atrial fibrillation (AF) is an international problem, which has often been attributed to the presence of contraindications to treatment. No studies have assessed the influence of contraindications on anticoagulant prescribing in the UK. To determine the influence of contraindications on anticoagulant prescribing in patients with AF in the UK. Cross-sectional analysis of primary care data from 645 general practices contributing to The Health Improvement Network, a large UK database of electronic primary care records. Twelve sequential cross-sectional analyses were carried out from 2004 to 2015. Patients with a diagnosis of AF aged ≥35 years and registered for at least 1 year were included. Outcome measure was prescription of anticoagulant medication. Over the 12 study years, the proportion of eligible patients with AF with contraindications who were prescribed anticoagulants increased from 40.1% (95% confidence interval [CI] = 38.3 to 41.9) to 67.2% (95% CI = 65.6 to 68.8), and the proportion of those without contraindications prescribed anticoagulants increased from 42.1% (95% CI = 41.6 to 42.6) to 67.7% (95% CI = 67.2 to 68.1). In patients with a recent history of major bleeding or aneurysm, prescribing rates increased from 44.3% (95% CI = 42.2 to 46.5) and 34.8% (95% CI = 29.4 to 40.6) in 2004 to 71.7% (95% CI = 69.9 to 73.5) and 63.2% (95% CI = 58.3 to 67.8) in 2015, respectively, comparable with rates in patients without contraindications. The presence or absence of recorded contraindications has little influence on the decision to prescribe anticoagulants for the prevention of stroke in patients with AF. The study analysis suggests that, nationally, 38 000 patients with AF with contraindications are treated with anticoagulants. This has implications for patient safety.