We appreciate the interest of Powell et al in our analysis of the hospitalisation burden associated with Clostridium difficile infection in patients with inflammatory bowel disease (IBD). Cross-sectional epidemiological studies can suggest an association but cannot directly prove causality. To that effect, we agree with the view of Powell et al that, while our results strongly suggest an association between C difficile infection and higher morbidity and mortality in patients with IBD, they do not directly prove causality. Indeed, we have acknowledged this limitation in our manuscript. …