BACKGROUND: Infective endocarditis (IE) in people who inject drugs (PWID) is an emergent public health problem. OBJECTIVES: The purpose of this study was to investigate IE in PWID and compare it with IE in non-PWID patients. METHODS: Two prospective cohort studies (ICE-PCS and ICE-Plus databases, encompassing 8,112 IE episodes from 2000 to 2006 and 2008 to 2012, with 64 and 34 sites and 28 and 18 countries, respectively). Outcomes were compared between PWID and non-PWID patients with IE. Logistic regression analyses were performed to investigate risk factors for 6-month mortality and relapses amongst PWID. RESULTS: A total of 7,616 patients (591 PWID and 7,025 non-PWID) were included. PWID patients were significantly younger (median 37.0 years [interquartile range: 29.5 to 44.2 years] vs. 63.3 years [interquartile range: 49.3 to 74.0 years]; p < 0.001), male (72.5% vs. 67.4%; p = 0.007), and presented lower rates of comorbidities except for human immunodeficiency virus, liver disease, and higher rates of prior IE. Amongst IE cases in PWID, 313 (53%) episodes involved left-side valves and 204 (34.5%) were purely left-sided IE. PWID presented a larger proportion of native IE (90.2% vs. 64.4%; p < 0.001), whereas prosthetic-IE and cardiovascular implantable electronic device-IE were more frequent in non-PWID (9.3% vs. 27.0% and 0.5% vs. 8.6%; both p < 0.001). Staphylococcus aureus caused 65.9% and 26.8% of cases in PWID and non-PWID, respectively (p < 0.001). PWID presented higher rates of systemic emboli (51.1% vs. 22.5%; p < 0.001) and persistent bacteremia (14.7% vs. 9.3%; p < 0.001). Cardiac surgery was less frequently performed (39.5% vs. 47.8%; p < 0.001), and in-hospital and 6-month mortality were lower in PWID (10.8% vs. 18.2% and 14.4% vs. 22.2%; both p < 0.001), whereas relapses were more frequent in PWID (9.5% vs. 2.8%; p < 0.001). Prior IE, left-sided IE, polymicrobial etiology, intracardiac complications, and stroke were risk factors for 6-month mortality, whereas cardiac surgery was associated with lower mortality in the PWID population. CONCLUSIONS: A notable proportion of cases in PWID involve left-sided valves, prosthetic valves, or are caused by microorganisms other than S. aureus.

Centre for Cardiovascular Surgery and Transplantation Brno Czech Republic; Faculty of Medicine Masaryk University Brno Czech Republic

Department of Infectious Disease Barwon Health and Deakin University Geelong Australia

Department of Microbiology Mater Misericordiae University Hospital Dublin Ireland

Department of Pathology and Biomedical Science University of Otago Christchurch New Zealand

Division of Infectious Diseases American University of Beirut Beirut Lebanon

Duke University School of Medicine Durham North Carolina USA

Hadassah Hebrew University Medical Center Jerusalem Israel

Infectious diseases and intensive care unit Pontchaillou University Hospital Rennes France

Infectious Diseases Department Hospital Clinic IDIBAPS University of Barcelona Barcelona Spain

Infectious Diseases Department Hospital Clinic IDIBAPS University of Barcelona Barcelona Spain; Department of Genetics Microbiology and Statistics University of Barcelona Barcelona Spain

Instituto Cardiovascular de Buenos Aires Buenos Aires Argentina

Instituto Nacional de Cardiologia and Unigranrio Rio de Janeiro Brazil

Internal Medicine University of Campania Monaldi Hospital Naples Italy

Servei de Malalties Infeccioses Hospital Universitari Vall d'Hebron Universitat Autònoma de Barcelona Barcelona Spain

J Am Coll Cardiol. 2021 Feb 9;77(5):556-558. doi: 10.1016/j.jacc.2020.11.058. PubMed

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