Risk factors for Clostridium difficile infection in hospitalized patients with community-acquired pneumonia

Objectives: Clostridium difficile infection (CDI) is strongly associated with anti-biotic treatment, and community-acquired pneumonia (CAP) is the leading indication for anti-biotic prescription in hospitals. This study assessed the incidence of and risk factors for CDI in a cohort of patients hospitalized with CAP. Methods: We analysed data from a prospective, observational cohort of patients with CAP in Edinburgh, UK. Patients with diarrhoea were systematically screened for CDI, and risk factors were determined through time-dependent survival analysis. Results: Overall, 1883 patients with CAP were included, 365 developed diarrhoea and 61 had laboratory-confirmed CDI. The risk factors for CDI were: age (hazard ratio [HR], 1.06 per year; 95% confidence interval [CI], 1.03-1.08), total number of antibiotic classes received (HR, 3.01 per class; 95% CI, 2.32-3.91), duration of antibiotic therapy (HR, 1.09 per day; 95% CI, 1.00-1.19 and hospitalization status (HR, 13.1; 95% CI, 6.0-28.7). Antibiotic class was not an independent predictor of CDI when adjusted for these risk factors (P > 0.05 by interaction testing). Conclusions: These data suggest that reducing the overall antibiotic burden, duration of antibiotic treatment and duration of hospital stay may reduce the incidence of CDI in patients with CAP.