Mortality of patients with antibiotic-associated diarrhoea: the impact of Clostridium difficile.

Previous studies have shown conflicting results concerning mortality related to Clostridium difficile infection. The objective of this study was to determine the impact of C. difficile infection on short- and long-term mortality in hospitalised patients with antibiotic-associated diarrhoea. We therefore undertook a prospective case-control study of 217 hospitalised patients who received antibiotics, developed diarrhoea and underwent stool enzyme immunoassay for C. difficile TOX A/B. The Kaplan-Meier and the log-rank test were used to determine univariate survival analysis and a Cox regression model for multivariate analysis of 28 day and long-term mortality. Fifty-two (24%) of the 217 patients who met the study criteria were positive for C. difficile TOX A/B. The crude 28 day and long-term mortality rates of the entire cohort were 12.4% and 56%, respectively. On Cox regression analysis, hypoalbuminaemia, impaired functional capacity and elevated serum urea levels were found to be the only independent and statistically significant variables associated with long-term mortality. C. difficile toxin positivity per se was not associated with increased short- or long-term mortality rates. In conclusion, hypoalbuminaemia, renal failure, and impaired function capacity predict mortality due to antibiotic-associated diarrhoea, but C. difficile involvement by itself does not further increase the risk of death in these patients.