Prevalence of Right- and Left-Sided Endocarditis Among Intravenous Drug Use Patients at a Large Academic Medical Center

BACKGROUND: Left-sided infective endocarditis (IE) is increasingly being recognized among intravenous drug use (IVDU) patients. We sought to assess the trends and risk factors that contribute to left-sided IE in this high-risk population at University of Kentucky. METHODS: A retrospective chart review of patients with the diagnosis of both IE and IVDU admitted at University of Kentucky was carried out from January 1, 2015 to December 31, 2019. Baseline characteristics, trends of endocarditis and clinical outcomes (mortality and in-hospital interventions) were recorded. RESULTS: A total of 197 patients were admitted for management of endocarditis. One hundred and fourteen (57.9%) had right-sided endocarditis, 25 (12.7%) had combined left-sided and right-sided endocarditis, and 58 (29.4%) had left-sided endocarditis. Staphylococcus aureus was the most common pathogen. Mortality and inpatient surgical interventions were higher among patients with left-sided endocarditis. Patent foramen ovale (PFO) was the most common shunt found (3.1%), followed by atrial septal defect (ASD, 2.4%) with PFO being significantly more common among patients with left-sided endocarditis. CONCLUSION: Right-sided endocarditis continues to be predominant among IVDU patients and Staphylococcus aureus was the most common organism involved. Patients with evidence of left-sided disease were found to have significantly more PFO, needed more inpatient valvular surgeries, and had higher all-cause mortality. Further studies are needed to assess if PFO or ASD can increase the risk of acquiring left-sided endocarditis in IVDU.