Time to monitor incidence after NICE guidance
BMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d121 (Published 11 January 2011) Cite this as: BMJ 2011;342:d121
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A correction is needed to my blog of 27 Jan 2011. It should read as
follows.
Unfortunately the NICE guidelines are logically flawed and therefore
invalid. It is quite easy to show this. The guidelines use the phrase
"there is no evidence....etc, etc" That indeed is true and there are many
possible reasons for the absence of evidence. Obviously with "no evidence"
the guidelines must be based on incomplete evidence. The guidelines
confuse "absence of evidence" (as in the phrase "there is no evidence")
with "evidence of absence" (as in "there is evidence that...say",
prophylaxis is not useful). We do NOT have the latter. See Bland and
Altman BMJ, 1995, 311, 485. The Black Swan, Nassim Nicolas Taleb 2007
Competing interests: No competing interests
Unfortunately the NICE guidelines are logically flawed and therefore
invalid. It is quite easy to show this. The guidelines use the phrase
"there is no evidence....etc etc". That indeed is true and there are many
possible reasons for the absence of evidence. Obviously with "no evidence"
the guidelines must be based on incomplete evidence. The guidelines
confuse "absence of evidence" (as in the phrase "there is no evidence")
with evidence of absence (as in "there is evidence that...say, prophylaxis
is not useful). We do have the latter.
See Bland and Altman BMJ,1995, 311, 485.
The Black Swan, Nassim Nicolas Taleb, 2007
Competing interests: No competing interests
Dr Stern's anecdotal impression of an increase in the incidence of
infective endocarditis since the NICE guidelines (1) maybe just that and
reaction should be delayed until evidence is available. Preliminary data
from our tertiary Adult & Paediatric Congenital Cardiac Centre refutes
his impression (but is also too premature to be conclusive).
All 21 patients presenting with endocarditis from April 2008 to
November 2010 were identified and assessed for prior or remedial dental
work and infecting organisms. Of the organisms detected, 11 were oral
pathogens (streptococcus viridans or salivarious or abiotrophia
defectivia), 4 were staphylococcus aureus, 2 nasopharyngeal commensals, 3
miscellaneous organisms and 1 was culture negative. In the 11 (52%)
patients with endocarditis due to an oral pathogen, in only 1 (9%) was
this temporally related to preceding dental work (without antibiotic
prophylaxis). One child had spontaneously shed deciduous teeth and one had
removal of a fixed brace (antibiotic prophylaxis not previously
recommended in these situations) (2). In four (36%) patients, severe
caries or dental abscesses were found after the episode of infective
endocarditis was diagnosed.
In this limited audit, there has not been a noticeable increase in
dental related episodes of IE since the change in guidance for antibiotic
prophylaxis - as was feared by many. Although the new guidelines have been
in place for only a short time, over 200 cases have now been reported to
the Central Cardiac Audit Database as requested by the British Congenital
Cardiac Association (BCCA) (3). A rigorous analysis of this data should
provide good evidence of the relationship of infective endocarditis to
dentistry.
The need for high levels of dental hygiene, however remain, and will
need greater emphasis now that our patients no longer carry antibiotic
prophylaxis cards and are therefore not reminded as frequently as in the
past. There appears to be a link with oral organisms but in earlier years,
dental attendance was more delayed than presently and it is possible that
the organisms were already in the blood stream/heart by the time of the
dental visit.
References
1) National Institute for Health and Clinical Excellence. CG64 prophylaxis
against infective endocarditis: full guidance. 2008.
http://guidance.nice.org.uk/CG64/Guidance/pdf/English.
2) American Heart Association. New guidelines regarding antibiotics
to prevent infective endocarditis. 2007.
www.americanheart.org/presenter.jhtml?identifier=3047051.
3) Response of the BCCA to the NICE Recommendations on Endocarditis
Prophylaxis (CG64) http://www.bcs.com/documents/bcca_response_to_NICE.doc
Competing interests: No competing interests
We agree with Stern (1) and other subsequent correspondents that
there is an urgent need to monitor the incidence of infective
endocarditis. The publication of our clinical guideline on Prophylaxis
against Infective Endocarditis (2) caused controversy in recommending that
antibiotic prophylaxis to prevent infective endocarditis should not be
given to adults and children with structural cardiac defects at risk of
infective endocarditis undergoing dental and non-dental interventional
procedures. We are aware of at least one PCT that has decided not to
implement the guideline fully. Since then NICE has received letters
reporting anecdotes of individual patients developing infective
endocarditis at some time after a dental procedure in the absence of
antibiotic prophylaxis. These are of course all personal tragedies but
they unfortunately do not add any further evidence to inform the debate
about the role of antibiotic prophylaxis or any future guidance.
The guideline made the following research recommendation: 'it is
noted that infective endocarditis is a rare condition and that research in
this area in the UK would be facilitated by the availability of a national
register of cases of IE that could offer data into the 'case' arm of
proposed case-control studies' (2) (p. 87). We have encouraged
cardiologists who have contacted us to take up this recommendation of a
national register of cases but are not aware of any attempt to set this
up.
1. BMJ 2011; 342:d121
2. National Institute for Health and Clinical Excellence. Prophylaxis
against
infective endocarditis 2008. (NICE clinical guideline No 64). Available at
http://www.
nice.org.uk/CG064.
Competing interests: TS, FM and PL are employees of NICE. TS led the NICE short clinical guidelines team that developed the prophylaxis against infective endocarditis guideline.
It is misleading of Dr Stern to cite the paper by Connaughton (1)
to support his assertion that 'the number of cases of endocarditis seems
to have noticeably increased'. The authors made no mention of any
suspicion that this has occurred. Dr Stern's observation of a 10-fold
increase since publication of the NICE guidance is, indeed, astonishing;
it may be due to the play of chance but clearly merits further study and I
trust that he and his specialist colleagues intend for this to be done. I
can certainly state that in the tertiary cardiac centre in which I work we
have not experienced an increase in the number of cases.
Nicholas H Brooks
Consultant Cardiologist
UHSM NHS Foundation Trust,
Wythenshawe Hospital,
Manchester M23 9LT
Nicholas.Brooks@uhsm.nhs.uk
Reference
1. Connaughton M, Rivett JG. Infective endocarditis.
BMJ 2010;341:c6596. (1 December)
Competing interests: Member of the NICE guideline development group on prophylaxis against infective endocarditis
Dear BMJ,
I agree monitoring of change is essential, but please don't forget
that one of the MAJOR reasons such Antibiotic cover was dropped as a
routine prescription before dental treatments, is because daily tooth
brushing and traumas in the mouth cause significant bacteraemias all the
time anyway, especially in those exhibiting common gum diseases and
bleeding gums, which is literally millions of our population.
Many people do not receive regular dental care or floss their teeth daily
to control their gum diseases and bleeding gums and frankly the Medical
Profession seems very poor at reminding patients with Heart conditions,
the immuno-compromised, Diabetics etc, etc. of the importance of getting
and maintaining good Dental Health!
Chronic dental infections like gum diseases must be controlled well
or people will be suffering regular daily bacteraemias with all the known
causative organisms of Endocarditis, as well as other medical
complications.
It has been estimated that millions of people with gum diseases have the
equivalent wound area the size of the inner forearm, so is it surprising
gum diseases are daily causes of dangerous bacteraemias, irrespective of
any dental treatments?
Clearly one-off Antibiotics are not a universal answer, indeed they have
simply created more generalised resistant strains in the population within
such daily bacteraemias, causing overall harm.
Regular dental check-ups and gum-cleanings control such gum diseases, but
only some 50% of the population access such routine dental care and my
medical colleagues know how many people still attend them with dental
infections/gum abscesses, because they cannot/will not go for proper
dental treatments.
So by all means monitor the changes since UK Dentists stopped
prescribing millions of Antibiotics for Endocarditis prevention
specifically, but as many of my Dental colleagues know, a much greater
significant risk is the non-Treatment of widespread gum diseases in the
population and their daily bacteraemias of pathogenic organisms. This may
even explain why any increases of Endocarditis cases occur even when no
dental treatments have happened, it may be BECAUSE they haven't happened!
My perception is that dental health risks seems to get completely
overlooked in any medical-assessment to individuals at risk of
Endocarditis or immunocompromised in any way. Why is this?
Maybe our Medical colleagues could simply ask such medically
vulnerable patients if they have bleeding gums daily and prescribe them
dental gum treatments as a priority, if they answer yes?
Medicine and Dentistry need better communication and understanding of
where the overall risks to health lie, then properly targeted prevention
can benefit our WHOLE population better, ideally in a proven and
synergistic way.
That would be my prescription.
Yours preventively,
Anthony Kilcoyne
Dental Specialist in Prosthodontics
Haworth, Yorkshire. UK.
Competing interests: I am a dental Specialist who often gets referred medically compromised patients for complex dentistry treatments.
Can I fully support Dr Stern's call for a system to be put in place
to monitor changes in the prevalence of endocarditis following publication
of the NICE guidance.
Indeed that guidance document stated:
"It is noted that infective endocarditis (IE) is a rare condition and that
research in this area in the UK would be facilitated by the availability
of a national register of cases of IE that could offer data into the
'case' arm of proposed case-control studies."
The reasons why there has been so much difference in advice over the
years is that the advice has been based on "expert" opinion and because
the extended time between infection and the appearance of symptoms makes
it difficult to undertake a clinical investigation.
The AHA document stated:
"The Committee believes that recommendations for IE prophylaxis must be
evidence based. A placebo-controlled, multicenter, randomized, double-
blinded study to evaluate the efficacy of IE prophylaxis in patients who
undergo a dental, GI, or GU tract procedure has not been done. Such a
study would require a large number of patients per treatment group and
standardization of the specific invasive procedures and the patient
populations"
It would be seem to be unlikely that funding for this could be found
from a stretched NHS budget so case control studies seem to be the only
way to try and find a reliable answer.
Because of the importance of having an answer surely every case of IE
should be registered centrally following a careful investigation into
preexisting factors and events in the patient's life during the year
preceding the diagnosis.
It is imperative that a thorough history and examination by an
experienced dentist takes place for each patient as there is good evidence
that everyday events in the mouth are as likely a cause of a bacteraemia
as an intervention by a dentist.
Dentists in the past became used to being blamed by by GPs and
Consultants for causing IE but before the blame game starts again lets
have the evidence.
The AHA document stated:
"IE is much more likely to result from frequent exposure to random
bacteremias associated with daily activities than from bacteremia caused
by a dental, GI tract, or GU tract procedure.
Prophylaxis may prevent an exceedingly small number of cases of IE,
if any, in individuals who undergo a dental, GI tract, or GU tract
procedure.
The risk of antibiotic-associated adverse events exceeds the benefit,
if any, from prophylactic antibiotic therapy.
Maintenance of optimal oral health and hygiene may reduce the
incidence of bacteremia from daily activities and is more important than
prophylactic antibiotics for a dental procedure to reduce the risk of IE."
The AHA document still advises antibiotic prophylaxis in some cases:
"In patients with underlying cardiac conditions associated with the
highest risk of adverse outcome from IE, IE prophylaxis for dental
procedures is reasonable, even though we acknowledge that its
effectiveness is unknown" In other words "expert" opinion prevails not
evidence.
If indeed cases of IE have increased 10-fold over the last few years
this is a serious public health issue and demands urgent efforts to find
the cause.
But please - no change in guidance before there is more high grade
evidence available.
Competing interests: I am a dentist who has lived through 7 changes of guidance from the AHA and probably as many or more changes in UK guidance
Endocarditis research database and prophylaxis RCT
Recent correspondence has highlighted concerns about the incidence of
infective endocarditis (IE), the potential impact of NICE endocarditis
prophylaxis guidelines on rates of IE and the need for more definitive
evidence about the effectiveness of different preventative strategies (1,
2). It is worth noting that an increase in the incidence of IE is
anticipated because of the increasing prevalence of key predisposing
factors such as degenerative valve disease in an ageing population, the
number of patients with prosthetic heart valves and implanted cardiac
devices, the number of patients who receive renal replacement therapy via
long-term vascular access devices, ongoing problems with intravenous drug
abuse and the expanding number of patients who become immunosuppressed.
Hospital episode statistics data for England and Wales from 2000 to 2010
show a steadily increasing rate of reporting of IE cases that would be
consistent with this. Introduction of the NICE guideline does not appear
to have significantly altered this trend despite a substantial reduction
in antibiotic prophylaxis prescribing (Thornhill et al BMJ in press).
However, because it is possible that residual prophylaxis prescribing is
directed at high-risk patients such as those with prosthetic valves, it is
not possible to exclude the possibility that such patients might benefit
from antibiotic prophylaxis. The potential difficulty in confirming or
refuting an association of endocarditis with recent dental or other
diagnostic or interventional procedures should not be under-estimated.
In response to calls for a system to monitor trends in the incidence
of endocarditis, we have recently established an endocarditis research
database and data collection is due to begin in pilot centres before being
rolled out nationally. The database includes a minimum dataset that is
simple to collect and will provide valuable information on the changing
epidemiology of the disease that could, as suggested by Dr Page (3), serve
to provide cases for a future case-control study. Implementation of the
NICE guideline in the United Kingdom may, by reducing the number of
patients who have received prophylaxis for their interventions, provide an
advantage over the existing Dutch, French and American epidemiological
studies and the International Collaboration on Endocarditis registry. We
would be delighted to hear from clinicians who might be interested in
joining the project.
The UKCRN Cardiovascular Speciality Clinical Study Group and the
British Heart Valve Society are planning a randomised placebo controlled
trial of antimicrobial prophylaxis for dental procedures in patients with
prosthetic heart valves. This will be a nationwide study involving a
large number of high-risk patients to ensure sufficient power to detect
any effect of prophylaxis. This will be able to determine whether the
lack of changes in incidence in endocarditis is attributable to persistent
selective treatment in high-risk individuals.
Finally, in response to comments made by Dr Ward (4), evidence from
case-control studies has so far failed to demonstrate an association
between interventional procedures (for non-infective indications) and the
development of endocarditis. Whilst it is impossible to prove that
endocarditis is never caused by an intervention, these studies indicate
that this is, at most, an exceptionally rare occurrence and that
prophylactic antimicrobial therapy could, at best, be only partially
protective.
1. Stokes T, Macbeth F, Littlejohns P. NICE calls for a register. Bmj
2011;342.
2. Stern SR. Time to monitor incidence after NICE guidance. Bmj
2011;342(7789):121-2.
3. Page J. Re:Time to monitor incidence after NICE guidance (rapid
response). British Medical Journal 2011;342(7789).
4. Ward DE. Re:Time to monitor incidence after NICE guidance (rapid
response). British Medical Journal 2011;342(7789).
Competing interests: No competing interests