This review, carried out by authors of the Cochrane Oral Health Group, has been produced to determine whether people at increased risk of bacterial endocarditis, a severe infection or inflammation of the lining of the heart chambers, should routinely take antibiotics before invasive dental procedures in order to reduce the incidence of endocarditis, the number of deaths, and the amount of serious illness this group of people experiences.
Bacterial endocarditis (BE) is a rare disease, it is generally accepted that 10 out of 100,000 people will suffer from it each year. The infection often occurs on previously damaged or malformed areas of the heart. It is usually treated with antibiotics, however BE is a life-threatening condition and up to 30% of people who suffer from it die, even with antibiotic treatment.
It is thought that invasive dental procedures may cause BE in people who are at risk of developing it. It is not known how many cases of BE (if any) are directly caused this way. Many dental procedures cause bacteraemia, which is the presence of bacteria in the blood, and although it is usually dealt with quickly by the body’s immune system, it has been believed that bacteraemia may lead to BE in a few at risk people. Guidelines in many countries have recommended that before undergoing invasive dental procedures, people at high risk of BE should be given antibiotics in order to reduce the possibility of BE occurring. However, recent guidance by the National Institute for Health and Care Excellence (NICE) in England and Wales has recommended that antibiotics are not required for any interventional procedure, either dental or surgical.
Some authorities have questioned the routine use of antibiotics, arguing that overprescription has resulted in the emergence of resistance of many organisms to common antibiotics, and also that the occasional adverse effects of antibiotics (severe allergic reactions) may outweigh the potential benefits.
The evidence on which this review is based was up to date as of January 2013.
The objective was to determine whether preventive (prophylactic) use of antibiotics, compared to no antibiotics or placebo, before invasive dental procedures in people at risk or at high risk of bacterial endocarditis influences the numbers of deaths, serious illness or incidence of endocarditis.
One study was included in this review, which compared the treatment of people at high risk of endocarditis who did develop BE and a group of people at high risk of endocarditis who did not develop BE. The study was an observational case-control study based in the Netherlands which looked at information about 349 people who contracted BE over a specific two year period. These people were matched to a similar group of people who had not contracted BE. All those participating in the study had undergone an invasive medical or dental procedure. The two groups were compared with regard to who had received preventive antibiotics before these procedures and those who did not.
It is unclear whether taking antibiotics as a preventive measure before undergoing invasive dental procedures is effective or ineffective against bacterial endocarditis in people at risk.
No studies were located that assessed numbers of deaths, serious adverse events requiring hospital admission, other adverse events, or cost implications of treatment.
There is a lack of evidence to support previously published guidelines in this area. It is not clear whether the potential harms and costs of antibiotic administration outweigh any beneficial effect. Ethically, practitioners need to discuss the potential benefits and harms of preventive antibiotic treatment with their patients before a decision is made about prescribing it.
Quality of the evidence
Although external factors relating to the study, such as inclusion of relevant participants and well defined parameters, were good, overall the observational and retrospective nature of the design of the study conferred a substantial risk of bias.