Condition category
Infections and Infestations
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Infective endocarditis (IE) is a serious infection of the heart. Around 30% of those who get IE die in the first year and survivors develop serious on going complications. Bacteria from the mouth are the cause in 35-45% of cases but it is not clear if these enter the blood during daily activities such as chewing food and tooth brushing, 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 people 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.

Who can participate?
Patients who has an IDP performed and have their details entered in either the Hospital Episode Statistics Database or NHS Business Services Dental Database.

What does the study involve?
This study looks at patient details in two national databases and uses the information contained to track every patient that has had a IDP performed to investigate whether they develop IE or not over the following year. Researchers then look at this data to see whether IE occurs more frequently in the three months directly after a IDP is performed.

What are the possible benefits and risks of participating?
Not provided at time of registration

Where is the study run from?
University of Sheffield (UK)

When is the study starting and how long is it expected to run for?
September 2016 to June 2021

Who is funding the study?
Health Technology Assessment Programme (UK)

Who is the main contact?
Professor Martin Thornhill

Trial website

Contact information



Primary contact

Prof Martin Thornhill


Contact details

University of Sheffield School of Clinical Dentistry
Claremont Crescent
S10 2TA
United Kingdom
+44 (0)1142717857

Additional identifiers

EudraCT number number

Protocol/serial number

HTA 15/57/32

Study information

Scientific title

The Invasive Dentistry - Endocarditis Association case-crossover study


The IDEA Study

Study hypothesis

The IDEA-Study will link national data on courses of dental treatment and hospital admissions for infective endocarditis (IE) to investigate if there is a temporal link or association between invasive dental procedures and the development of IE.

1. Our Null hypothesis is that: There is no temporal association between invasive dental procedures and the development of IE. If the null hypothesis is proven, this would suggest there is no rationale for AP and AP is unlikely to be effective in preventing IE. It would suggest other prevention strategies, such as improving oral hygiene, are likely to be more effective in preventing IE
2. Our alternative hypothesis is that: There is a temporal association between invasive dental procedures and the development of IE.

Ethics approval

Because this study will only utilise publically available national data that have been linked and anonymised by the Health and Social Care Information Centre (HSCIC) before being made available to us, it will not require NHS ethics approval via NRES. It will, however, require us to apply through HSCIC’s Data Access Request Service (DARS) to use the data. As part of this process we also need approval from the Data Access Advisory Group (DAAG). DAAG is an independent group, hosted by HSCIC, which considers applications for sensitive data made to the HSCIC's Data Access Request Service.

Study design

A case-crossover design study

Primary study design


Secondary study design

Case crossover study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a patient information sheet


Infective endocarditis


This is an observational study using UK national databases to see if infective endocarditis hospital admissions occur with higher frequency in the 3 months immediately following a course of treatment at a dentists that includes an invasive dental procedure than in later 3 month control periods.

Using personal details to link 2 national databases every patient who has an IDP performed will be identified and tracked them see if they develop IE or not over the following year.

If IDP are linked to IE, researchers expect IE cases to peak in the 3 months after an IDP (since IE develops within 3 months of infection with a causal bacteria). If instead, activities such as tooth brushing enable oral bacteria to cause IE, IE cases are expected to be evenly spread throughout the year.

Comparisons will also be made as regards to 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.

Dental visits are identified 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.

Intervention type



Drug names

Primary outcome measure

The incidence of infective endocarditis (IE) hospital admissions in the 3 months immediately following courses of dental treatment that includes an invasive dental procedure, coopered to the incidence of IE hospital admissions during later 3 month periods (3-6, 6-9 and 9-12 months after)

Secondary outcome measures

1. The frequency of courses of dental treatment involving an invasive dental procedure (cases) before an IE diagnosis
2. The frequency of course of dental treatment that did NOT involve an invasive dental procedure
The two outcomes are then compared.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. All IE hospital admissions in England between 1st April 2010 and 31st March 2016 recorded on the Hospital Episode Statistics database
2. All individuals within England who attended an NHS dentist for a check up or treatment between 1st April 2009 and 31st March 2016 and whose data is recorded on the NHS Business Services Dental Database

Participant type


Age group




Target number of participants

Our Estimates indicate there will be 1,483 admissions for IE who had an invasive dental procedure in the previous 12 months.

Participant exclusion criteria

1. Individuals falling into the target population without a known NHS number
2. Individuals with missing or corrupt records

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University of Sheffield
S10 2TA
United Kingdom

Sponsor information


University of Sheffield

Sponsor details

Western Bank
S10 2TN
United Kingdom

Sponsor type




Funder type


Funder name

Health Technology Assessment Programme

Alternative name(s)

NIHR Health Technology Assessment Programme, HTA

Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

The data will be of interest to both dentists and cardiologists and will be presented at appropriate Cardiology and Dental scientific meetings. The 2018 European Society of Cardiology (ESC) meeting in Munich or the 2018 American Heart Association (AHA) meeting will be targeted and the International Association for Dental Research meeting in July 2018. If the data is suitable, a manuscript will also be prepared for publication in an appropriate cardiology, general medical or dental journal.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

09/07/2020: The trial contact details have been made publicly visible. 12/12/2018: The following changes were made to the trial record: 1. The recruitment end date was changed from 30/11/2018 to 30/06/2020. 2. The overall trial end date was changed from 30/11/2018 to 30/06/2021. 3. The intention to publish date was changed from 31/07/2019 to 31/06/2022.