Association of Intravenous Drug Use and Length of Stay Following Infective Endocarditis

Intravenous drug use (IVDU) and associated infective endocarditis (IE) has been on the rise in the US since the beginning of the opioid epidemic. IVDU-IE has high morbidity and mortality, and treatment can be lengthy. We aim to quantify the association between IVDU and length of stay (LOS) in IE patients.

The National Inpatient Sample database was used to identify IE patients, which was then stratified into IVDU-IE and non-IVDU-IE groups. Weighted values of hospitalizations were used to generate national estimates. Multivariable linear and logistic regression analyses were applied to estimate the effects of IVDU on LOS.

We identified 1,114,257 adult IE patients, among which 123,409 (11.1%) were IVDU-IE. Compared to non-IVDU-IE patients, IVDU-IE patients were younger, had fewer comorbidities, and had an overall longer LOS (median [interquartile range]: 10 [5-20] versus 7 [4-13] d, P < 0.001), with a greater percentage of patients with a LOS longer than 30 d (13.7% versus 5.7%, P < 0.001). After adjusting for multiple demographic and clinical factors, IVDU was independently associated with a 1.25-d increase in LOS (beta-coefficient = 1.25, 95% confidence interval [CI]: 0.95-1.54, P < 0.001) and 35% higher odds of being hospitalized for more than 30 d (odds ratio = 1.35, 95% CI: 1.27-1.44, P < 0.001).

Among IE patients, being IVDU has associated with a longer LOS and a higher risk of prolonged hospital stay. Steps toward the prevention of IE in the IVDU population should be taken to avoid an undue burden on the healthcare system.