Does accepted definition of Clostridioides difficile infection (CDI) severity predict poor outcomes in older adults?

Background: Advanced age is an important factor affecting Clostridioides difficile infection (CDI) risk and outcome. While fever and leukocytosis are prominent findings in young individuals with CDI, they are usually blunted in the elderly. Furthermore, chronic kidney disease often exists among this population prior to the CDI episode onset. Aim: We aimed to examine whether the accepted definition of severe CDI (leukocytosis ≥ 15,000 cells/μl or serum creatinine > 1.5 mg/dl) predicts poor outcomes in the elderly. Methods: All CDI hospitalized individuals between January-2013 and May-2020 were included. The study population was dichotomized into older group (≥ 65 years) and younger group (< 65 years). Primary composite outcome was 30-day mortality, colectomy due to severe colitis, or intensive care unit admission. The older group was divided according to the primary outcome to evaluate the effect of CDI severity criteria. Results: The study included 853 patients. Of them, 571 were in the older group and 282 in the younger one. The primary outcome was significantly more common in the older group (93/571, 16% vs. 31/282, 11%; p = 0.04). Ninety days mortality was significantly higher in the older group [116/571, 20% vs. 30/282, 11%; p < 0.01]. In multivariate analysis, accepted CDI severity criteria were not significantly associated with poor outcomes (odds ratio [OR] = 1.2, 95% confidence interval [CI] 0.7–2.2, p = 0.5). Advanced dementia and low serum albumin were significant predictors of poor outcomes (OR = 3, 95%CI 1.5–6, p = 0.002 and OR = 3.1, 95%CI 1.7–5.8, p < 0.01). Conclusion: The accepted definition of CDI severity was not useful in predicting CDI poor outcomes in older adults. In this population, we suggest advanced dementia and low albumin among others as CDI severity markers.