Emergency department eosinophil counts and mortality in Clostridium difficile: a multihospital retrospective cohort study.

Abstract

Background: Clostridium difficile (Clostridioides difficile) infection (CDI) is the most common nosocomial infection in the United States, with mortality rates approaching 25% within 2 months of diagnosis. While current guidelines focus on CDI management once systemic symptoms develop, limited research has explored early predictors of disease severity. Eosinophils play a key role in gut immunity, and prior studies suggest absolute eosinopenia may be associated with severe CDI. This study evaluates the relationship between initial emergency department eosinophil counts and in-hospital mortality, with secondary assessments of admission rates, length of hospital stay, vasopressor use, and the need for surgical intervention.

Methods: We conducted a retrospective cohort study across 3 hospitals from July 1, 2018, to September 1, 2019. Adult patients with a positive Clostridium difficile stool assay and a documented eosinophil count during their emergency department evaluation were included. Patients already on CDI treatment, those younger than 18 years, and those without eosinophil counts were excluded. The primary outcome was in-hospital mortality. Secondary outcomes included admission rates, length of hospital stay, vasopressor use, and surgical intervention. Eosinophil counts were categorized 0.0 cells/μL (absolute eosinopenia) and >0.0 cells/μL. Odds ratios and relative risks were calculated with 95% confidence intervals.

Results: Among 326 patients, 56 had eosinophil counts of 0.0 cells/μL, while 270 had counts >0.0 cells/μL. Patients with eosinophil counts of 0.0 cells/μL had higher mortality (16% vs. 6%, OR: 2.98, 95% CI: 1.25-7.15), increased admission rates (87% vs. 57%, OR: 5.05, 95% CI: 2.23-11.41), and longer hospital stays (7.1 vs. 3.4 days, P < .001). No significant differences were observed in vasopressor use or surgical intervention.

Conclusions: An initial emergency department eosinophil count of 0.0 cells/μL is associated with increased mortality, admission rates, and prolonged hospital stays in CDI. Absolute eosinopenia may serve as an early prognostic marker for disease severity, warranting further prospective investigation.