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PRACTICE: Mark Connaughton Commentary: Controversies in NICE guidance on infective endocarditis BMJ 2008; 336: 771 [Full text]

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Seemly Advice Is Illogical

Rubin Minhas   (7 April 2008)

Antimicrobial prophylaxis against infective endocarditis

David Wray, Roberta Richey, Francis Ruiz, and Tim Stokes   (8 April 2008)

Seemly Advice Is Illogical 7 April 2008
Rubin Minhas, General Practitiioner Sunlight Medical Centre, Richmond Road, Gillingham, Kent. ME7 1LX Send response to journal: Re: Seemly Advice Is Illogical	The suggestion that the NHS should compensate those who might suffer as a result of moving away from the practice of routine prescribing of antibiotics for the prophylaxis of infective endocarditis1 is illogical. If patients who experienced 'serious reactions' (now to be ‘hugely reduced’) as a result of routine antibiotics were not offered compensation before, invoking a novel ‘responsibility’ for the arguable effects of changing this policy is inconsistent. Arguments to authority that rest on eminence, expertism or august bodies to support a conclusion can be logically fallacious, particularly where cited authorities do not possess a knowledge or perspective of the entire area under discussion2, where expert’s disagree3 or because they may be wrong4. ‘Long established clinical practice’ is also not a logical basis for establishing the validity of a course of action. This ‘appeal to popularity’ suggests that a belief is true because it is widely held. This is a fallacy because popular opinion can be, and often is, mistaken. It was on this basis that for several centuries a majority of the population believed that the Earth was either flat or located at the centre of the universe. Those who suggested otherwise received considerable ‘flak’. As far as this represented ad hominem arguments or arguments based on incredulity, they were also fallacious. Given the paucity of evidence in the current 'controversy', highlighting the relative absence of trial evidence might be more useful i.e. the potential fallacy of an appeal to ignorance. This, together with the issues of what constitutes ‘evidence’, when it is enough, who decides and the process of medical reasoning seem to be the crux of the issue. 1. Connaughton M. Commentary: Controversies in NICE guidance on infective endocarditis. BMJ 2008;336:771, doi:10.1136/bmj.39512.666412.AD 2. Marks N. An expert witness falls from grace. BMJ 2003;327:110 (12July), doi:10.1136/bmj.327.7406.110 3. Dowdall N P.‘Most experts agree’. BMJ 2008;336:684 (29March),doi:10.1136/bmj.39525.512176.3A 4. Mayor S. Authors reject interpretation linking autism to MMR vaccine. BMJ 2004;328:602 (13March), doi:10.1136/bmj.328.7440.602-c Competing interests: RM is both a member of the British Cardiovascular Society and a participant in NICE guidelines and guidance.
Antimicrobial prophylaxis against infective endocarditis 8 April 2008
David Wray, professor of oral medicine glasgow dental school, glasgow G2 3JZ, Roberta Richey, Francis Ruiz, and Tim Stokes Send response to journal: Re: Antimicrobial prophylaxis against infective endocarditis	We would like to thank Connaughton in his commentary on the NICE prophylaxis against infective endocarditis guideline (www.nice.org.uk/CG064) for noting that the guideline recommendations are clear and based on a detailed review of the evidence. We would, however, take issue with three assertions made by Connaughton.1 First, that “one searches in vain for clarity about what is recommended”, particularly with respect to advice to patients. We fully recognise that this guideline represents a major shift to current practice and that advice to this effect will need to be offered to patients and would highlight that NICE are developing a suite of implementation tools for this guideline to achieve this (http://www.nice.org.uk/usingguidance/implementationtools/implementation_tools.jsp). Second, that the “recommendations are undoubtedly flawed in not providing positive indications of when to give antibiotics”. It is a central thrust of the guideline that antibiotic prophylaxis to prevent infective endocarditis is not recommended for patients undergoing the interventional procedures covered by the guideline. This recommendation is based on a systematic review of the literature and a de novo health economic model regarding dental antibiotic prophylaxis. This evidence shows there is no consistent association between having an interventional procedure, dental or non-dental, and the development of infective endocarditis; regular toothbrushing almost certainly presents a greater risk of infective endocarditis than a single dental procedure because of repetitive exposure to bacteraemia with oral flora; the clinical effectiveness of antibiotic prophylaxis is not proven and antibiotic prophylaxis against infective endocarditis for dental procedures is not cost effective and may lead to a greater number of deaths through fatal anaphylaxis than a strategy of no antibiotic prophylaxis. Third, “it would be seemly for NICE to suggest that the NHS might adequately compensate anyone whose health suffered as a consequence of the new guidelines”. It is outside the remit of NICE’s work to offer such advice, which in any case is at odds with the guideline recommendations, and the detailed evidence review that underpins them. NICE is required to make judgements on the clinical and cost-effectiveness of a wide range of health care interventions based on the best available evidence at the time of guideline development. In addition, NICE has mechanisms in place to ensure that its guidance is reviewed as necessary. We would like to conclude by noting that the NICE guideline is not alone on the international stage in terms of recommending a much more limited role for antibiotic prophylaxis against infective endocarditis prior to interventional procedures. The recent American Heart Association guideline does exactly this.2 Thus it is likely that the future will see consensus among health care professional groups that antibiotic prophylaxis is not indicated, a view based on the best available evidence of clinical and cost effectiveness. David Wray chair, Prophylaxis against Infective Endocarditis NICE guideline; professor of oral medicine, university of glasgow; d.wray@dental.gla.ac.uk Roberta Richey, Technical Analyst, Centre for Clinical Practice, NICE Francis Ruiz, Technical Advisor (Health Economics), Centre for Clinical Practice, NICE Tim Stokes, Associate Director, Centre for Clinical Practice, NICE 1. Connaughton M. Commentary: controversies in NICE guidance on infective endocarditis. BMJ 2008;336:771. 2. Wilson W, Taubert K, Gewitz M et al. (2007) Prevention of Infective Endocarditis. Guidelines from the American Heart Association. A Guideline From the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation 2007;116:1736-54. Competing interests: DW was chair of the NICE prophylaxis against infective endocarditis guideline and RR, FR and TS were members of the short clinical guidelines technical team.