Clostridioides difficile infection (CDI) is a disease with high morbidity and mortality rates. The objective of this study was to describe CDI epidemiology and patient characteristics over a 5-year period in Switzerland and assess risk factors for mortality, recurrence and severe CDI.

We retrospectively included all consecutive CDI cases having occurred in adult patients hospitalized in two tertiary centers: the Lausanne University Hospital (1000 beds) and the University Hospital of Zurich (900 beds), between 2014 and 2018. Suspected cases of CDI were identified from the microbiology laboratory database on the basis of a positive test and confirmed by records review.

During first CDI episodes, the median age was 67 years and the median Charlson comorbidity index (CCI) score was 5. All in all, 299 out of 826 patients (36.2%) had severe infection based on the Infectious Diseases Society of America criteria. In the multivariable analysis, CCI was associated with increased risk of mortality. None of the factors recorded on admission were significantly associated with increased risk of recurrence. In the multivariable analysis, male sex and CCI were associated with severity, while immunosuppression was associated with less severe presentation.

If we did not identify any criteria on admission that could be predictive of recurrences, this could be explained the retrospective nature of the study. A higher comorbidity index is a key driver for severe CDI and mortality. Reporting of CDI is not mandatory in Switzerland; structuration of CDI reporting should be a short-term priority.