Patients with injection drug use (IDU)-related infective endocarditis (IE) have higher rates of readmission for endocarditis, septicemia, and drug abuse compared with those whose IE is not related to IDU, according to results published in the Journal of the American College of Cardiology.

The study included participants with IE identified from the National Readmissions Database between January 2010 and September 2015. The researchers stratified participants by IDU status and surgical vs medical management. They used Kruskal-Wallis and chi-square tests to analyze baseline differences by IDU status, and they used multivariable regressions to analyze the primary and secondary outcomes.

The study’s primary outcome was 30-day readmission and cause. Secondary outcomes included mortality, length of stay (LOS), adjusted costs, and 180-day readmission.

In total, the researchers identified 96,344 non-IDU-IE participants and 27,431 people with IDU-IE. Between 2010 and 2015, the percentage of IDU-IE cases increased from 15.3% to 29.1% (P <.001).

At baseline, participants with IDU-IE had reduced mortality (6.8%) compared with those with non-IDU-IE (9.6%, P<.001). However, IDU-IE was not associated with 30-day readmission compared with non-IDU-IE (23.8% vs 22.9%; P =.077).

Participants with medically-managed IDU-IE had higher LOS (β=1.36 days; 95% CI, 0.71 to 2.01), reduced costs (β=-$4427; 95% CI, -$7093 to -$1761), increased readmission for endocarditis (18.1% vs. 5.6%; P <.001), increased readmission for septicemia (14.0% vs. 7.3%; P <.001), and increased readmission for drug abuse (4.3% vs. 0.7%; P <.001) compared with medically managed non-IDU-IE.

Participants with surgically-managed IDU-IE had increased LOS (β, 4.26 days; 95% CI, 2.73-5.80), readmission for septicemia (15.6% vs 5.2%; P <.001), and readmission for drug abuse (7.3% vs 0.9%; P <.001) compared with surgically-managed non-IDU-IE.

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“Increased focus on addiction treatment and social support following hospital discharge has the potential to mitigate both the human and economic impacts of IDU-IE,” the researchers wrote.

Reference

Rudasill SE, Sanaiha Y, Mardock AL, et al. Clinical outcomes of infective endocarditis in injection drug users. J Am Coll Cardiol. 2019;73(5):559-570.