Long-Term Outcomes of Infective Endocarditis in Injecting Drug Users

Overview

This retrospective study assessed 5-year outcomes of infective endocarditis (IE) in people who inject drugs (PWID) compared to non-PWID with community-acquired IE. PWID had a significantly higher risk of recurrent IE episodes and similar 1- and 5-year mortality rates compared to non-PWID. Injection drug use, female gender, and comorbidity were independent predictors of mortality.

Background

Infective endocarditis in PWID is a distinct clinical entity often involving right-sided valves and Staphylococcus aureus infection. While short-term prognosis in PWID is better than in non-PWID, long-term outcomes remain poorly characterized. Ongoing intravenous drug use and socioeconomic factors may contribute to poorer long-term survival and higher recurrence rates. This study fills a gap by providing population-based 5-year follow-up data comparing PWID and non-PWID with community-acquired IE.

Data Highlights

Key Findings

• PWID with IE had a significantly higher risk of new IE episodes within 5 years compared to non-PWID (20% vs 5%; OR 4.65; P = .003).
• One-year mortality rates were similar between PWID and non-PWID groups (4.0% vs 4.1%).
• Five-year mortality was higher in PWID (18.7%) than non-PWID (13.3%), but this difference was not statistically significant (P = .399).
• Injection drug use (OR 12.2), female gender (OR 2.62), and higher age-adjusted comorbidity index independently predicted death during 5-year follow-up.
• Most PWID (86%) received addiction specialist consultation during hospitalization, and 44% were on medications for opioid use disorder (MOUD) at discharge.
• Buprenorphine and amphetamines were the most commonly used substances among PWID with IE.

Clinical Implications

Clinicians should recognize that PWID with IE are at increased risk for recurrent IE and have poor long-term survival despite similar short-term mortality compared to non-PWID. Integration of addiction treatment, including MOUD and specialist consultation during hospitalization, is critical to improve outcomes. Close follow-up and strategies to reduce ongoing injection drug use may reduce recurrence and mortality.

Conclusion

PWID with infective endocarditis face a high risk of recurrent infection and poor long-term survival. Enhanced addiction treatment efforts are essential to improve prognosis in this vulnerable population.

References

1. Kauko et al. 2024 -- Long-Term Outcomes of Infective Endocarditis in Injecting Drug Users: A Five-Year Retrospective Study