Antibiotic prophylaxis for infective endocarditis after dental procedures: is the guidance toothless?

Most of the changing, evidence-based guidance we talk about at NB Medical is iterative; it builds on what comes before, practice is altered, modified, but seldom completely reversed.  When that happens, it takes some adjustment, there’s always a mental jolt when something we were told was “pass/fail” for a viva or OSCE is tipped on its head. 

The first time this happened to me was early in my career, when in 2008, NICE published guidance on antibiotic prophylaxis for those patients at risk of infective endocarditis (IE).  Medical school cardiology had drilled into me the need for all structural heart disease patients to have an antibiotic dose before dental work.  But subsequently, NICE were clear that we should consider this outmoded, and those of us working back then will remember patients needed a lot of reassurance about the change. 

It’s worth remembering that infective endocarditis is a dangerous condition, with a one-year mortality rate of 40%. So, it felt to me that NICE were taking a bold step, but the guidance was widely adopted.  It was notable that both US and European colleagues didn’t change their guidance, however.  There was also uncertainty around the fact that the phrasing was that antibiotic prophylaxis shouldn’t be “routinely” used with no definition of what that meant; a form of words that was cited in one letter to me from a tertiary centre colleague.

This guidance has been reviewed, but not changed materially, since.  NICE still do not routinely advocate antibiotic prophylaxis, and maintained that position despite 2015 evidence that demonstrated  a clear decrease in prescribing, and a clear increase in IE incidence. 

We may need to do more than gesture furtively at NICE now, with the publication last month of a new Lancet paper that strongly suggests that the guidance is revisited.  Last year, the European Society of Cardiology strengthened their recommendation for antibiotic prophylaxis before invasive dental procedures in high-risk patients, and the American Heart Association agrees with that position, making NICE seem very much an outlier.  The article reviews research since 2015, and whilst some of the individual studies seem limited, the collective weight of the evidence does come down in favour of the strength of the association between invasive dental procedures and IE, and also of the efficacy and safety of antibiotic prophylaxis.   This is important news for the nearly 400,000 high risk individuals in the UK – and for us, who will almost invariably be caring for some of them in each of our practices.  The authors anticipate that reverting the guidance would prevent between 41-261 IE cases per year, and that includes 12-78 deaths.  They also helpfully reassure us about that the concerns around anaphylaxis rates and antibiotic resistance are unfounded and can evidence that with one study showing no fatal adverse drug reactions in over 3 million amoxicillin prescriptions. 

The authors acknowledge that their position is not informed by any RCT data; but as they also point out, such a study would be practically impossible, both in terms of the size needed and more importantly the ethical considerations.  In any case, I find their presentation of the data in what is a short and highly readable paper compelling.  Their call for action is being picked up in the media and I think we will soon see this (generally well-informed) patient group asking us about this in our clinics – alongside the inevitable queries about prescribing from our dental colleagues.  It is worth noting that the paper stops short of recommending specific regimens for prophylaxis, but the European guidance referenced is advocating 2g of oral amoxicillin for adults (with useful suggested alternatives).  This will cover the oral streptococci that are the main target in these patients.

At the time of writing, the NICE guidance stands.  I think it’s also worth reflecting that the poor oral hygiene and dental condition risks of IE are not in any way helped by the very strained position of NHS dentistry, and there will be colleagues reading this who will not unreasonably think that our dental colleagues should ideally be managing this issue, and not us. However, the queries will still arise, and I’d agree with the concluding statement from the authors:

In our view, a review of NICE guidance is now essential so that high-risk patients in the UK can benefit from the same protection afforded these patients in the rest of Europe and the world.