The Epidemiology of Infective Endocarditis: A Two-Decade Retrospective Longitudinal Analysis

Background: Infective endocarditis (IE) is a rare yet serious condition affecting the heart valves and the endocardium. Notably, there has been a shift in the risk-factor profile from traditional factors such as rheumatic heart disease and poor dental health to more iatrogenic causes such as prosthetic heart valves, cardiac devices, foreign body implants, haemodialysis, and immunosuppression. Purpose: While IE has been extensively studied in the past, the evolving landscape prompts an epidemiological re-evaluation of vulnerable patient populations. Our primary objective is to examine the trends in microbiological and echocardiographic diagnostics over two decades and to compare them across native valve endocarditis (NVE), prosthetic valve endocarditis (PVE), and cardiac implantable electronic device-related IE (CIED-IE). Methods: We conducted a retrospective analysis of longitudinal data encompassing 912 patients admitted with either a possible or definite IE diagnosis between 2001 and 2023. Results: The incidence of IE increased over the study duration (p<0.01) with octogenarians most affected (21%). Iatrogenic risk factors were associated with nearly two-thirds (63%) of patients diagnosed with IE, while traditional risk factors were evident in almost one-eighth (13%). Blood culture-negative endocarditis increased over the study duration (19% versus 27%, p<0.01) and Staphylococcus aureus (29%, p<0.01) became the dominant pathogen over Viridans group streptococci (14%, p=0.001). Imaging with transthoracic (56% in 2004 versus 75% in 2023) and transoesophageal echocardiography (57% in 2004 versus 79% in 2023) had an increasing contribution in the diagnosis of IE over the two decades. The subgroup analysis suggested that PVE and CIED-IE were more likely to have negative blood cultures (OR=3.7, CI [1.2-6.8] & OR=4.9, CI [1.3-8]) compared to NVE (OR=0.04, CI [0.02-0.8]). PVE and CIED-IE were more likely to have inconclusive echocardiographic imaging (OR=3.7, CI [1.2-6.6] & OR=2.2, CI [0.07-7.8]) compared to NVE (OR=0.63, CI [0.3-3.2]). Conclusion: Our study underscores the evolving nature of IE, now predominantly a healthcare-related disease. Diagnostic challenges persist due to the heterogeneity of the disease, with the emergence of distinct entities such as PVE and CIED-IE.