Authors' objectives: Infective endocarditis (IE) is a serious infection of the heart. Around 30% of those who get IE die in the first year and many survivors develop serious on going complications. Bacteria from the mouth are the cause in 35-45% of cases but it is not clear to what extent these enter the blood during daily activities such as chewing food and tooth brushing, particularly in those with poor oral hygiene, or during invasive dental procedures (IDP) e.g. extractions, dental scaling or root canal treatment. Because of the possible link to IDP, the focus of IE prevention has been to give antibiotics to those at risk of IE before any IDP. This is called antibiotic prophylaxis (AP) and is the standard of care for individuals at high-risk of IE in most of the world. However, there has never been a clinical trial to test if AP works. Because of this, NICE (National Institute for Health & Care Excellence) recommended that AP stop in 2008 and the UK is now the only country where AP is not recommended for patients at high-risk of IE. A recent study, however, found a significant increase in IE following introduction of the 2008 NICE guideline. This has raised serious concerns about the advice not to give AP in the UK. However, for AP to be effective there must be a causal link between IDP and IE, and the purpose of this study is to determine if there is a link or not. Using personal details to link 2 national databases we will identify every patient who has an IDP performed and track them see if they develop IE or not over the following year. If IDP are linked to IE we would expect IE cases to peak in the 3 months after an IDP (since we know that IE develops within 3 months of infection with a causal bacteria). If instead, activities such as tooth brushing enable oral bacteria to cause IE, we would expect IE cases to be unrelated to IDP. As a further check, we can compare the occurrence of IE following a visit to the dentist that includes an IDP with the occurrence following a visit that does not include an IDP. We can identify all dental visits because dentists complete a form for each patient they treat and send it to the NHS Business Service Authority in order to be paid. This records patient details and the types of dental procedure performed, including IDP, during each visit. IE patients are all admitted to hospital and we can identify them using the Hospital Episode Statistics database. This records the diagnosis and personal details of every hospital admission. NOTE: The NHS Health & Social Care Information Centre (guardian of these 2 databases) will link patient data across the 2 databases and anonymise it before making it available to us. The research team will therefore have no identifying information about patients in the study. The study is important because there are ~2,000 IE cases a year requiring intensive treatment often involving open-heart surgery and long hospital stays, Unfortunately, ~600 will die in the first year and survivors are at high-risk of further problems and require intensive long-term care. The cost to individuals, families, society and the NHS is very high. So if there is a link between IDP and IE, the financial, personal and societal savings resulting from AP could be very large. Alternatively, if no link exists, the costs and risks (antibiotic resistance and adverse drug reactions) of AP can be avoided and prevention re-focussed on improving oral hygiene in those at risk of IE.

Project Status: Ongoing

URL for project: http://www.nets.nihr.ac.uk/projects/hta/155732

Anticipated Publish Date: 2021

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: England, United Kingdom

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk

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