Oral health and infective endocarditis among high-risk individuals: a nationwide register-based study

Background Poor oral health has long been hypothesized as a contributor to infective endocarditis caused by Viridans group streptococci (VGS-IE), particularly among individuals at increased risk of the disease. However, large-scale population-based evidence remains sparse.Objective Assess the association between severe oral disease and IE among high-risk individuals using Swedish nationwide health registers.Design Nested case-control study conducted within a national cohort of 64,634 individuals at high risk of IE due to prior IE, prosthetic heart valves, or congenital heart disease (CHD), followed between July 1, 2008, and December 31, 2018. 881 cases of IE and 8,810 controls were identified using the National Patient Register and the Swedish Registry of Infective Endocarditis. Poor oral health was defined using the Swedish Dental Health Register. Conditional logistic regression was used to estimate odds ratios (ORs) for poor oral health in cases versus controls, adjusted for age, sex, educational attainment and comorbidities.Results Among individuals with prior IE, poor oral health was associated with both all-cause IE and VGS-IE. All-cause IE: adjusted OR 3.02 (95% CI 1.95–4.69). VGS-IE: adjusted OR 2.23 (95% CI 1.02–4.90). Among those with prosthetic valves, no significant associations were observed (all-cause IE: adjusted OR 1.47 [95% CI 0.94–2.30]; VGS-IE: adjusted OR 1.09 [95% CI 0.44–2.71]). No conclusions could be drawn for the CHD-group due to a lack of data.Conclusions Poor oral health was associated with IE recurrence among individuals with a history of IE, suggesting a role for oral health in prevention strategies.