Invasive dental treatments (IDTs) have been considered a potential risk factor of infective endocarditis (IE); however, the association between IDTs and IE remains controversial. Ms. Tzu-Ting Chen, a doctoral student at the National Taiwan University, her advisor Dr. Yu-Kang Tu, a professor in the Institute of Epidemiology and Preventive Medicine in the College of Public Health, and their research team used a large national cohort in Taiwan to answer this question. Their study has been published on July 24 in Circulation.
It is challenging to investigate the association between IDTs and IE, because IDTs are extremely common and it is, therefore, hard to find a comparable group who have never received IDTs. In addition, the power of statistical analysis is often insufficient, because IE is a rare and acute event. Ms. Chen et al. used two case-only study designs, such as case-crossover design and self-controlled case series design, to undertake within-subject comparisons. The advantage of case-only study is that time-invariant confounding factors are adjusted for implicitly.
In total, 9120 and 8181 patients with IE were included in the case-crossover and self-controlled case series design, respectively. In the case-crossover design, the odds ratios were 1.12 (95 percent confidence interval (CI), 0.94-1.34), 1.05 (95 percent CI, 0.91-1.20), 1.06 (95 percent CI, 094-1.19), and 1.07 (95 percent CI, 0.96-1.19) for 4, 8, 12, and 16 weeks, respectively. In the self-controlled case series design, the age-adjusted incidence rate ratios were 1.14 (95 percent CI, 1.02-1.26), 1.08 (95 percent CI, 0.96-1.21), 1.06 (95 percent CI, 0.94-1.19), and 1.12 (95 percent CI, 0.99-1.26), during 1 to 4, 5 to 8, 9 to 12, and 13 to 16 weeks after IDTs, respectively.
In conclusion, Ms. Chen et al. did not observe an association between IDTs and a larger risk for IE in the short period following IDTs, with consistent findings obtained from both study designs. They also did not find an association between IDTs and IE among patients with a high risk of IE, such as those with rheumatic heart disease or valve replacement. The risk of IE was very similar between IDTs with and without antibiotic prophylaxis. Antibiotic prophylaxis did not seem to provide any substantial benefit on the prevention of IE in the Taiwanese population. Their results suggest that the recommendations of antibiotics prophylaxis for the prevention of IE should be reassessed considering new evidence of the potential risk of adverse drug reactions to antibiotic prophylaxis. Therefore, they concluded that “The association between IDTs and IE may have been overstated previously, and a more practical approach to the dental treatment of patients with high risk of IE should now be considered.”