Clinical Characteristics and Factors Associated With Mortality in First-Episode Infective Endocarditis Among Persons Who Inject Drugs.

Importance: Persons who inject drugs (PWID) represent a distinct demographic of patients with infective endocarditis. Many centers do not perform valvular surgery on these patients owing to concerns about poor outcomes. Addiction services are underused in hospitals. Objectives: To compare clinical characteristics in first-episode infective endocarditis in PWID who are surgically vs medically managed and to identify variables associated with mortality. Design, Setting, and Participants: This case series studied PWID treated for a first episode of infective endocarditis between April 1, 2007, and March 30, 2016. Participants were adult patients (aged ≥18 years) admitted to any of 3 hospitals in London, Ontario, Canada. Analysis occurred between July 2016 and November 2017. Main Outcomes and Measures: Survival among PWID; the causative organisms, site of infection, and cardiac as well as noncardiac complications; referral to addiction services; and surgical vs medical management. Results: Of 370 total first-episode cases of infective endocarditis, 202 (54.6%) were in PWID. Among PWID, 105 (52%) were male, the median (interquartile range) age was 34 (28-42) years, and patients were predominantly positive for the hepatitis C virus (69.8% [141 of 202]). Right-sided infection was more common (61.4% [124 of 202]), and most infections were caused by Staphylococcus aureus (77.2% [156 of 202]). Surgery occurred in 19.3% of patients (39 of 202). The all-cause mortality rate was 33.7% (68 of 202). Adjusting for age and sex, survival analysis demonstrated that surgery was associated with lower mortality (hazard ratio [HR], 0.44; 95% CI, 0.23-0.84; P = .01), as was referral to addiction treatment (HR, 0.29; 95% CI, 0.12-0.73; P = .008). Higher mortality was associated with left-sided infection (HR, 3.26; 95% CI, 1.82-5.84; P < .001) and bilateral involvement (HR, 4.51; 95% CI, 2.01-10.1; P < .001). Conclusions and Relevance: This study presents the demographic characteristics of first-episode infective endocarditis in PWID. Results highlight the potentially important role of addictions treatment in this population. Further study to optimize selection criteria for surgery in PWID is warranted.