AIMS: Stratification of patients at risk of infective endocarditis (IE) remains a cornerstone in guidance of prophylactic strategies of IE. However, little attention has been given to patients considered at moderate risk.

METHODS AND RESULTS: Using Danish nationwide registries, we assessed the risk of IE in patients with aortic and mitral valve disorders, a cardiac implantable electronic device (CIED), or hypertrophic cardiomyopathy (HCM) and compared these patient groups with (i) controls from the background population using risk-set matching and (ii) a high-risk population (prosthetic heart valve). Cumulative incidence plots and multivariable adjusted Cox proportional hazard analysis were used to compare risk of IE between risk groups. We identified 83 453 patients with aortic or mitral valve disorder, 50 828 with a CIED, and 3620 with HCM. The cumulative risk of IE after 10 years was 0.9% in valve disorder, 1.3% in CIED, and 0.5% in HCM patients. Compared with the background population, valve disorder, CIED, and HCM carried a higher associated risk of IE, hazard ratio (HR) = 8.75 [95% confidence interval (CI) 6.36-12.02], HR = 6.63 (95% CI 4.41-9.96), and HR = 6.57 (95% CI 2.33-18.56), respectively. All three study groups were associated with a lower risk of IE compared with high-risk patients, HR = 0.27 (95% CI 0.23-0.32) for valve disorder, HR = 0.28 (95% CI 0.23-0.33) for CIED, and HR = 0.13 (95% CI 0.06-0.29) for HCM.

CONCLUSIONS: Heart valve disorder, CIED, and patients with HCM were associated with a higher risk of IE compared with the background population but have a lower associated risk of IE compared with high-risk patients.