For patients with Clostridium difficile infections, undetectable peripheral eosinophils at admission were a significant predictor of severe outcomes, even in the absence of hypotension and tachycardia, researchers wrote in JAMA Surgery.

This illustration depicts the ultrastructural morphology exhibited by a single Gram-positive Clostridium difficile bacillus. CDC/Jennifer Hulsey

“In animal models, peripheral eosinopenia is a biologically plausible predictive factor for adverse outcomes, and human data from this study indicate that this frequent addition to an admission complete blood cell count is an inexpensive, widely available risk index in the treatment of C. difficile infection,” wrote Audrey S. Kulaylat, MD, of Penn State University, Hershey, and her associates.

In their cohort study of 2,065 patients admitted to two tertiary referral centers with C. difficile infection, undetectable eosinophil counts at hospital admission were associated with significantly increased odds of in-hospital mortality in both a training dataset (odds ratio, 2.01; 95% confidence interval, 1.08-3.73; P = .03) and a validation dataset (OR, 2.26; 95% CI, 1.33-3.83; P = .002). Undetectable eosinophil counts also were associated with elevated odds of severe disease requiring intensive care, vasopressor use, and emergency total colectomy. Besides eosinopenia, significant predictors of mortality included having more comorbidities and lower systolic blood pressure at admission. Strikingly, when patients had no initial hypotension or tachycardia, an undetectable eosinophil count was the only identifiable predictor of in-hospital death (OR, 5.76; 95% CI, 1.99-16.64). An elevated white blood cell count was not a significant predictor of mortality in this subgroup.

Dr. Kulaylat and her associates are studying the microbiome in C. difficile infection. Their work has identified a host immune reaction marked by an “exaggerated inflammasome response” and peripheral eosinopenia, they explained. Two recent murine models have produced similar results.

Admission eosinophil counts “allow for an immediate assessment of mortality risk at admission that is inexpensive and part of a differential for a standard complete blood count available at any hospital,” they concluded. They are now prospectively evaluating a prognostic score for C. difficile infection that includes eosinopenia and other easily discernible admission factors. The National Institutes of Health supported the work. The researchers reported having no conflicts of interest.

SOURCE: Kulaylat AS et al. JAMA Surg. 2018 Sep 12. doi: 10.1001/jamasurg.2018.3174.