Clinical profile of injection drug users presenting to the ED.

Background: Injection drug users (IDUs) commonly use the emergency department (ED) as their primary health care access point.

Objective: We sought to characterize infectious disease clinical presentations and laboratory results of IDUs admitted to the hospital from the ED and contrast them with those of non-IDUs.

Methods: We enrolled all admitted adult patients with infectious disease-related diagnoses at a county level 1 trauma center from June 2010 to January 2011 and used a structured chart abstraction tool to record patient characteristics and clinical outcomes. We compared clinical presenting features, laboratory data, and microbiological culture results of IDUs with concomitantly enrolled non-IDUs.

Results: Of 603 total participants, 189 were IDUs, and 414 were non-IDUs. Injection drug users had higher rates of skin and soft tissue infection admission but had similar hospital length of stay (7.5 vs 6.1 days) and mortality (2.1% vs 2.9%). Compared with non-IDUs, IDUs more commonly had hyponatremia, 38.1% vs 27.1% (mean difference, 11.4%; 95% confidence intervals [CIs], 3.4%-19.6%) and thrombocytopenia, 18.5% vs 11.0% (mean difference, 7.5%; 95% CI, 1.5%-14.2%) but less frequently had leukocytosis, 36.0% vs 52.7% (mean difference, 16.7%; 95% CI, 8.2%-24.8%). Injection drug users and non-IDUs had similar rates of positive ED-derived blood cultures, 16.5% vs 22.6% (mean difference, 6.1%; 95% CI, -13.3 to 1.7%).

Conclusions: When admitted from the ED for infectious disease-related diagnoses, IDUs had similar rates of fever, higher rates of hyponatremia and thrombocytopenia, and lower rates of leukocytosis than non-IDUs. Although they had similar rates of bacteremia, only IDUs were positive for methicillin-resistant Staphylococcus aureus.