Predicting a complicated course of Clostridium difficile infection at the bedside

Clostridium difficile infections (CDIs) are a common cause of antibiotic-associated diarrhoea and associated with CDI-related mortality in c. 10%. To date, there is no prediction model in use that guides clinicians to identify patients at high risk for complicated CDI. From 2006 to 2009, nine Dutch hospitals included hospitalized CDI patients in a prospective cohort. Potential predictors of a complicated course (ICU admission, colectomy or death due to CDI) were evaluated in uni- and multivariate logistic regression. A score was constructed that was internally validated by bootstrapping. Furthermore, a pilot external validation was performed. Twelve per cent of 395 CDI patients had a complicated course within 30 days after diagnosis. Age (≥85 years, OR 4.96; 50-84 years, 1.83), admission due to diarrhoea (OR 3.27), diagnosis at the ICU department (OR 7.03), recent abdominal surgery (OR 0.23) and hypotension (OR 3.25) were independent predictors of a complicated course. These variables were used to construct a prediction model. A score subsequently classified patients into high risk (39% with a complicated course), intermediate (16%), low (5%) or virtually no risk of experiencing a complicated course. The score performed well after internal validation (AUC 0.78) and a pilot external validation among 139 patients showed similar good performance (AUC 0.73). We present an easy-to-use, clinically useful risk score that is capable of categorizing CDI patients according to their outcome. Because classification is available at diagnosis, it could have major implications for treatment choice.