Evaluation of risk factors for a fulminant Clostridium difficile infection after cardiac surgery: a single-center, retrospective cohort study

BACKGROUND: Clostridium difficile (CD) is the most common pathogen causing nosocomial diarrhea. The clinical presentation ranges from mild diarrhea to severe complications, including pseudomembranous colitis, toxic megacolon, sepsis, and multi-organ failure. When the disease takes a fulminant course, death ensues rapidly in severe and complex cases. Preventive screening or current prophylactic therapies are not useful. Therefore, this study was conducted to detect risk factors for a fulminant CD infection (CDI) in patients undergoing cardiac surgery. METHODS: Between April 1999 and April 2011, a total of 41,466 patients underwent cardiac surgery at our institution. A review of our hospital database revealed 1256 patients (3.0%) with post-operative diarrheal disease who tested positive for CD; these patients comprised the cohort of this observational study. A fulminant CDI occurred in 153 of these patients (12.2%), which was diagnosed on the basis of gastrointestinal complications, e.g. pseudomembranous colitis, and/or the need for post-cardiac surgery laparotomy. Demographic, peri-operative, and survival data were analyzed, and predictors of a fulminant CDI were assessed by binary logistic regression analysis. RESULTS: The 30-day mortality was 6.1% (n = 77) for the entire cohort, with significantly higher mortality among patients with a fulminant CDI (21.6% vs. 4.0%, p < 0.001). Overall mortality (27.7%, n = 348) was also higher for patients with a fulminant course of the disease (63.4% vs. 22.8%, p < 0.001), and a laparotomy was required in 36.6% (n = 56) of the fulminant cases. Independent predictors of a fulminant CDI were: diabetes mellitus type 2 (OR 1.74, CI 1.15–2.63, p = 0.008), pre-operative ventilation (OR 3.52, CI 1.32–9.35, p = 0.012), utilization of more than 8 units of red blood cell concentrates (OR 1.95, CI 1.01–3.76, p = 0.046) or of more than 5 fresh-frozen plasma units (OR 3.38, CI 2.06–5.54, p < 0.001), and a cross-clamp time > 130 min (OR 1.93, CI 1.12–3.33, p = 0.017). CONCLUSIONS: We identified several independent risk factors for the development of a fulminant CDI after cardiac surgery. Close monitoring of high-risk patients is important in order to establish an early onset of therapy and thus to prevent a CDI from developing a fulminant course after cardiac surgery.