Do invasive dental procedures cause prosthetic joint infections?
The aim of the study was to identify if there is any association between the occurrence of invasive dental procedures and the development of late prosthetic joint infections (LPJI).
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. This is called antibiotic prophylaxis (AP).
The purpose of AP is to reduce the risk of bacteremia occurring following invasive dentistry which 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 at preventing LPJI. Currently, AP is not recommended in the UK for individuals with prosthetic joints but is widely used by dentists in the US when treating patients with prosthetic joints.
Study aims
The aim of the study was to identify if there is any association between the occurrence of invasive dental procedures and the development of LPJI. If there is no association between invasive dental procedures and the subsequent occurrence of LPJI, then there is no rationale for giving AP before invasive dental procedures to patients with prosthetic joints to prevent LPJI.
Methods
The PJI study linked national data on courses of dental treatment and hospital admissions for LPJI. English hospital admissions data was used to identify people who developed an LPJI between April 2010 and March 2017. This was then linked to routinely collected data for NHS dental treatment.
If invasive dental procedures were a cause of LPJI, we would expect to see more dental procedures in the three months immediately preceding the LPJI. By contrast, if there is no causal link then the incidence of dentistry should remain at similar rates across time.
This study is called a case-crossover design. We compared the incidence of invasive dentistry in the three months prior to LPJI hospitalisation (which we referred to as the "case period") to that over the 12 months immediately previous (the "control period"). We also looked at alternative case and control periods, including four-month and six-month periods.
We used data from England for two primary reasons. Firstly, the NHS holds comprehensive routinely collected data for the entire population (approximately 55 million). Secondly, in some countries (such as the US), people with prosthetic joints are often prescribed AP before invasive dental procedures, which would dilute any association between the two.
AP is not recommended nor routinely used in the UK for this purpose and any association between invasive dental procedures and LPJI should therefore be fully exposed. Our research was important to decide whether there is any link and whether antibiotics should be recommended for these people.
What we found
A total of 9427 LPJI hospital admissions with dental records were identified: their average age was 67 years and 52% were male. 25% had hip prosthetic joints, 34% had knee prosthetic joints, 3% had other prosthetic joints and the remaining 38% were unknown types.
We found no temporal association between invasive dentistry and subsequent LPJI. Indeed, there was a slight (11%) relative reduction in invasive dentistry in the three months prior to LPJI. The incidence for dentistry in the case period compared to control periods was 0.89 (95% confidence interval, 0.82 to 0.96; P =0 .002).
What this means
The burden of LPJI remains considerable: in the US alone, there are approximately 20,000 LPJI cases each year with around $560 million in annual treatment costs. However, our findings suggest that invasive dentistry does not cause LPJI and that AP is unnecessary and of no benefit for people with prosthetic joints when they undergo dentistry.
In the US, stopping this practice would reduce prescription costs of around $60 million annually for AP as well as the risk of adverse drug reactions to the antibiotics used and the potential to promote the development of antibiotic resistance through the unnecessary use of antibiotics.
Outcomes
The results of this study were published open access in the Journal of the American Medical Association (JAMA) Network Open. This study provided the first hard evidence to validate the stance taken in the UK, where the use of AP in patients with prosthetic joints is not recommended before invasive dental procedures to prevent LPJI.
In the US, where AP is still widely used, this evidence led to calls for the practice of giving AP to prosthetic joint patients undergoing invasive dental procedures to cease, both in the dental literature (J Am Dent Assoc 2022 Vol. 153 Issue 8 Pages 737-739) and the orthopaedic literature (J Arthroplasty 2022 Vol. 37 Issue 7 Pages 1223-1226).
Indeed, there are now calls for the Scientific Advisory Committee of the American Dental Association to produce definitive guidance against the use of AP for LPJI prevention following invasive dental procedures. These calls have been reinforced by the recent publication of two US studies that were performed as a direct result of the UK PJI study.
These studies, one performed in patients with employer-provided medical/dental insurance and the other in Medicaid patients, both found no significant association between invasive dental procedures and the subsequent occurrence of LPJI reinforcing the findings of the UK PJI study. Additionally, because some patients were given AP cover while others were not, these studies were able to investigate AP efficacy in preventing LPJI.
Neither study was able to demonstrate any effect of AP in reducing the risk of LPJI. The studies were published together in the Journal of the American Dental Association (JADA) (J Am Dent Assoc 2023 Vol. 154 Issue 1 Pages 43-52 e12).
Who funded this study?
This study was funded by the National Institutes for Health in the USA.
Protection of participants (including research ethics approval)
This study involved linking data held on two large National Health Service (NHS) databases – the NHS Digital Database, which holds data on all hospital admissions in England and the NHS Business Services Authority (NHSBSA) Dental Database, which holds data on all NHS courses of dental treatment in England.
The NHSBSA used patient identifying information to link these two sets of data, removed patient identifying information and transferred the data to the research team at the University of Sheffield. The overall data retention period for the project ends on 30/06/2024, and all original personal data has now been securely deleted.
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 (CAG reference: 18/SC/0387). The Sponsor and Data Controller for this study is the University of Sheffield.
Study registration
This study was registered as a clinical trial with the international clinical trial registry. More details can be found on the National Institutes for Health website.