Three Separate Clinical Entities of Infective Endocarditis—A Population-Based Study From Southern Finland 2013–2017

BACKGROUND: Health care–associated infective endocarditis (HAIE) and intravenous drug use–related IE (IDUIE) have emerged as major groups in infective endocarditis (IE). We studied their role and clinical picture in a population-based survey. METHODS: A population-based retrospective study including all adult patients diagnosed with definite or possible IE in Southern Finland in 2013–2017. IE episodes were classified according to the mode of acquisition into 3 groups: community-acquired IE (CAIE), HAIE, and IDUIE. RESULTS: Total of 313 episodes arising from 291 patients were included. Incidence of IE was 6.48/100 000 person-years. CAIE accounted for 38%, HAIE 31%, and IDUIE 31% of IE episodes. Patients in the IDUIE group were younger, and they more frequently had right-sided IE (56.7% vs 5.0%; P < .001) and S. aureus as etiology (74.2% vs 17.6%; P < .001) compared with the CAIE group. In-hospital (15.1% vs 9.3%; P = .200) and cumulative 1-year case fatality rates (18.5% vs 17.5%; P = .855) were similar in CAIE and IDUIE. Patients with HAIE had more comorbidities, prosthetic valve involvement (29.9% vs 10.9%; P = .001), enterococcal etiology (20.6% vs 5.9%; P = .002), and higher in-hospital (27.8% vs 15.1%; P = .024) and cumulative 1-year case fatality rates (43.3% vs 18.5%; P < .001) than patients with CAIE. Staphylococcus aureus caused one-fifth of IE episodes in both groups. CONCLUSIONS: Our study indicates that in areas where injection drug use is common IDUIE should be regarded as a major risk group for IE, along with HAIE, and not seen as part of CAIE. Three different risk groups, CAIE, HAIE, and IDUIE, with variable characteristics and outcome should be recognized in IE.