Preventive AF Anticoagulants Still Erroneously Prescribed

A new study shows that many doctors do not heed atrial fibrillation (AF) safety guidelines and still recommend anticoagulants to prevent stroke, even when contraindicated.

Researchers at the University of Birmingham (UB; United Kingdom) conducted a study that included 12 sequential annual cross-sectional analyses of data from 645 general practices across the United Kingdom contributing to the Health Improvement Network (HIN), a large database of electronic primary care records. The study, conducted between 2004 to 2015, included patients with a diagnosis of AF aged 35 years and up and who were and registered in the HIN for at least one year. The outcome measure was prescription of anticoagulant medication.

The results revealed that the proportion of eligible patients with AF who were prescribed anticoagulants increased from 40.1% to 67.2% during the 12-year period, while the proportion of patients without AF contraindications prescribed anticoagulants increased from 42.1% to 67.7%. In patients with a recent history of major bleeding or aneurysm, prescribing rates in patients with AF contraindications rose from 34.8% to 63.2%, suggesting that 38,000 patients at risk in the UK are treated with anticoagulants. The study was published on June 19, 2017, in the British Journal of General Practice.

“Because anticoagulants prevent strokes in people with this type of irregular pulse, GPs are encouraged to prescribe more anticoagulants to those who need them. This has been happening, and it is good news,” said lead author Nicola Adderley, MD, of the UB Institute of Applied Health Research. “But the sting in the tail is that more people who perhaps shouldn’t be on anticoagulants are also taking them. We need to understand the reasons for this and whether patients might come to any harm.”

Oral anticoagulants reduce the risk of thromboembolic events associated with AF, but many high-risk patients do not take them due to contraindications that create an unfavorable risk/benefit profile. AF patients with absolute contraindications to warfarin anticoagulation therapy include those with recent trauma or surgery, thrombocytopenia, hemorrhagic stroke, and alcoholism. Warfarin therapy is also not indicated for low-risk patients.

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