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GPs reminded not to prescribe anticoagulants to at-risk patients

A new study suggests almost 40,000 patients with an irregular heartbeat are being treated with anti-coagulants, even though they are at risk of adverse effects.

GPs are recommended to prescribe anticoagulants, such as warfarin, to patients with arrhythmia to reduce their risk of stroke.

However, anticoagulants also increase the risk of bleeding and safety advice recommends against their use in patients who are at risk of complications, for example if they have an ulcer, are pregnant or have previously had a stroke due to bleeding.

To test whether these recommendations are being put into practice, researchers from the University of Birmingham investigated whether contraindications influence anticoagulant prescribing in the UK.

The study, published in the BJGP today, reviewed patient records from 645 GP surgeries over 12 years (2004–2015). The researchers found that patients with atrial fibrillation and contraindications to anticoagulants were just as likely to be prescribed the drugs as those without any risk factors.

Author of the study Professor Tom Marshall said the situation did not change over time: 'Safety advice seems not to influence prescribing of anticoagulants. Patients considered a safety risk were just as likely to be prescribed the drugs. It was the same in every year from 2004 to 2015.'

He added GPs have been encouraged to prescribe anticoagulants to prevent strokes, but there needs to be more awareness of the risks.

Professor Marshall said: ‘The sting in the tail is that more people who perhaps shouldn’t be on anticoagulants are also taking them: about 38,000 nationally. We need to understand the reasons for this and whether patients might be come to any harm.’

NICE guidance on the management of atrial fibrillation clearly states that anticoagulants should only be used in the absence of contraindications.

The authors say more research is needed to understand why GPs prescribe anticoagulants to at-risk patients, and whether some patients with contraindications might still benefit from anticoagulant treatment.

Conversely, a study from the University of Birmingham published last year urged GPs to prescribe more preventive drugs. The study found that approximately one-third of stroke and mini-stroke (TIA) patients could be missing out on preventive drugs.

Readers' comments (6)

  • Dear All,
    So did they see an increase in the risk events actually happening in the patients they identified as being incorrectly treated? I'd have imagined it would be easy to spot, they had all the records. Or perhaps these are theoretical risks not seen in the real world of community medicine?
    PauL C

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  • I think the current recommendations have thrown caution to the wind and encouraged prescribing of anti-coagulants where there has been significant resistance in the past. Pharma pushing NOACs had also not helped. Personally I think we have gone too much in favour of anti-coagulation and will see the effects in years to come. There is considerable pressure to prescribe by CCGs, opinion leaders and pharma to reduce stoke risk and the bleeding risks are being downplayed. Falls are no longer considered a significant risk, Guidance states HASBLED should not be used as a guide to deny anti-coagulation but to mitigate risk factors. I am even seeing patients with cerebral bleeds after a fall being told to see their GP to restart anti-coagulation in 2 weeks time! I really dont think thats a decision I should be making!

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  • locally secondary care are usings noacs where contraindicated at the wrong dose or not in licence....even where we have been told not to by the manufacturers

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  • Most inappropriate initiation I am seeing seems to be coming from secondary care.But they should know better as they wear white coats and scrubs!

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  • Most inappropriate prescribing I have seen is from secondary care namely a&e

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  • Some really interesting points raised in the comments.

    It might help if I explained a bit more about how we did the study. We looked at all AF patients in a series of snapshots. We identified which AF patients had a prescription for anticoagulants and which did not on a specific date in each of a series of years. We then categorised them according to whether or not they had contraindications.

    Contraindications were defined as a clinically coded diagnosis of:
    major bleeding (gastrointestinal, intracranial, intraocular, retroperitoneal),
    aneurysm (within the previous 2 years),
    haemorrhagic stroke (within the previous 2 years),
    bleeding disorders (within the previous 2 years) (haemophilia, thrombocytopenia etc),
    peptic ulcer (within the previous 2 years),
    oesophageal varices (within the previous 2 years),
    proliferative retinopathy (within the previous 2 years);
    allergy or adverse reaction to anticoagulants (ever);
    pregnancy (within previous 9 months);
    severe hypertension (mean of 3 most recent blood pressures 200/120 mm Hg)
    Most contraindications were major bleeding, the next most common were aneurysm and haemorrhagic stroke.

    It is a really good question whether these recorded contraindications were really associated with more adverse events. This would require us to extract a very different set of data: the longitudinal records of AF patients on anticoagulants to see how many bleeding events and strokes they subsequently had. We suggested this type of analysis in the discussion.

    Yours sincerely
    Tom Marshall

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