PJI

Background

Prosthetic (artificial) replacement of poorly functioning, painful and diseased joints is now a common procedure. However, late prosthetic joint infections (LPJI), caused by blood-borne bacteria (bacteremia), are a common complication with high morbidity, and potential mortality, as well as high treatment, patient and societal costs. In an attempt to reduce the risk of LPJI, dentists in some parts of the world (particularly the USA) are recommended to give prosthetic joint patients antibiotics before invasive dental procedures (IDP). This is called antibiotic prophylaxis (AP). The purpose of this is to reduce the risk of a bacteremia occurring following an IDP that might result in infection of the prosthetic joint. However, there is little evidence for any association between IDP and LPJI and there are no clinical trial data demonstrating if AP is effective or not. Currently AP is not recommended in the UK for individuals with prosthetic joints, but is recommended in the US. Data proving or disproving any association between IDP and LPJI is urgently needed.

Study aims

The aim of the study is to identify if there is any association between the occurrence of invasive dental procedures and development of LPJI.

Methods

The PJI-Study will link national data on courses of dental treatment and hospital admissions for LPJI to investigate if there is a link between invasive dental procedures and the development of LPJI. We will address the following questions:

• Is the frequency of invasive dental procedures higher in the 3 months immediately before someone develops a LPJI than in other 3-month periods?
• Is the incidence of LPJI higher in the 3 months immediately following an invasive dental procedure than in the 3 months following dental treatments that do NOT involve an invasive dental procedure?

What are the possible outcomes of this study?

If an association exists, then the widespread adoption of AP in the UK and elsewhere could help reduce the number of LPJI cases each year and the high associated treatment costs. In the US alone, there are ~20,000 LPJI cases each year with a ~$566 million annual treatment cost.

Alternatively, if no association exists, then AP is unnecessary and a clear recommendation against its use could be made. As AP is not currently recommended in the UK this would not have a significant impact other than reassuring clinicians and patients about the safety of this approach. In the US, and other countries where AP is the standard of care, however, stopping AP would save ~$60 million annually, avoid the risk of adverse reactions in those who currently receive AP and reduce the risk posed to society that the use of antibiotics for AP might unnecessarily promote the development of antibiotic resistant bacteria.

Who are potential participants in the study?

All individuals admitted to hospital for late prosthetic joint infections (LPJI) in England.

What does the study involve?

This study uses national hospital admissions data to identify all those individuals in England who developed a LPJI in the period between 1st April 2010 and the 31st March 2017. Data on LPJI hospital admissions will then be linked to national data on NHS dental treatment to see if those who developed LPJI were more likely, or not, to have had an invasive dental procedure in the 3 months immediately preceding the LPJI than in any other 3-month period.

What are the possible risks and benefits of being a participant? 

If this study demonstrates a link between invasive dental procedures and LPJI, this will provide support for the use of antibiotic prophylaxis (AP) before invasive dental procedures in patients with prosthetic joints. If no such link is identified, it will provide reassurance to those with prosthetic joints, their dentists and physicians, carers and those charged with providing guidance on such issues, that current UK guidance not to provide AP for those with prosthetic joints is correct.

In countries such as the US, where AP is recommended for those with prosthetic joints undergoing invasive dental procedures, the demonstration of a link between invasive dental procedures and LPJI would lend support for this guidance. On the other hand, if no link was demonstrated, it would provide support for the concept that AP might not be necessary.

While this research will not directly benefit individuals in the data set, it will help to improve evidence-based dental care for all those with prosthetic joints. As it is an observational study, there is no direct risk for participants.

Who is funding this study?

This study is being funded by the National Institutes for Health in the USA.

Protection of Participants (including Research Ethics Approval)

This study involves linking data held on two large National Health Service (NHS) databases – The NHS Digital Database that holds data on all hospital admissions in England and the NHS Business Services Authority (NHSBSA) Dental Database that holds data on all NHS courses of dental treatment in England. This is necessary to allow us to identify any patients admitted to hospital in England with PJI, to look at their prior admissions to hospital in order to determine the date of any previous joint replacement surgery, and to confirm the timing of any invasive dental treatment they might have received in the preceding year. Patient identifying information already held by the NHS will be used by NHSBSA to link these two sets of data. However, this will be done entirely by the NHS. No patient identifying information (such as name, date of birth or address) will be made available to the researchers. All identifiable data will be removed by the NHS data managers before any data is made available to the research team; all data received by the research team will be ‘pseudonymised’ (i.e. NHS Digital will assign a non-identifying ID number to each record, in place of the deleted identifiable information such as names, dates of birth etc.). No record-level data used in this study will be transferred to any third country or international organisation at any point. The overall Data Retention Period for the project ends on 30/06/2024, and all original personal data will be securely deleted by this date.

As part of the funding process, this study was subject to rigorous independent scientific review. It was then submitted to the UK’s National Research Ethics Service for ethical evaluation and received full ethical approval on the 5th December 2018 (REC reference: 18/SC/0387 and IRAS project ID: 246818). In addition, because the study involves the use of national patient data records held by NHS Digital (hospital admission data) and the NHS Business Services Authority (dental treatment data), without seeking individual patient consent, the study was submitted to the Confidentiality Advisory Group (CAG). This is an independent body which provides expert advice on the use of confidential patient information – including providing advice to the Health Research Authority (HRA). The CAG approved this project (subject to this information being made publicly available on the University of Sheffield website) on the 4th December 2018 (CAG reference: 18/SC/0387) effectively giving permission for the study to start. The Sponsor and Data Controller for this study is the University of Sheffield. Please see the University of Sheffield General Privacy Notice for information on the handling of personal data by the university for research (e.g. this study), including details of the data protection officer, supervisory authority, right of complaint, and lawful basis for data processing under GDPR.

What can I do if I don’t want my data used in this study?

Despite the above safeguards, should any individual wish to have data related to them excluded from the study, i.e. wish to exercise their Patient’s Right of Objection to their data being used for research, or their Right to Erasure (‘right to be forgotten’) under article 17 of GDPR, they should contact the PJI Study Team at pji-group@sheffield.ac.uk requesting that their data be excluded from the study, and providing their full name, sex, date of birth and address details, so that NHS Digital / NHSBSA can identify their data and exclude it from any data extraction or linkage performed in connection with this study. This study involves no decision making or profiling that would produce a legal or other significant effect on any participant. Anyone who does not want confidential patient information held about them by NHS Digital (or the NHS Business Services Authority) to be used in this, or any other research, can also use the National data opt-out programme to have it excluded. Patients can find out more and set their opt-out choice at: https://www.nhs.uk/your-nhs-data-matters/.

Further information

This study is registered as a clinical trial with the international clinical trial registry ISRCTN at: http://www.isrctn.com/ISRCTN11310789. This web site provides further details relating to this study. In addition, the Funder (NIH) also has a web site that provides more detail about the study and its funding at: https://projectreporter.nih.gov/project_info_description.cfm?aid=9566332&icde=41935261