Obesity as a risk factor for Clostridium difficile infection.

BACKGROUND Obesity and Clostridium difficile infection (CDI) are both related to an increased Firmicutes/Bacteroidetes ratio in the intestinal microbiota. However, an association between obesity and CDI is unknown. We aimed to assess the association between obesity and CDI in hospitalized patients. METHODS We conducted a retrospective case-control study. From January to December 2011, all consecutive patients hospitalized with CDI, in 2 internal medical departments in 2 hospitals, were included. Patients with CDI were compared to hospitalized patients without diarrhea, during the same period and in the same departments, and matched by age, sex, Charlson score, length of hospitalization, and antibiotic use during the last 3 months. RESULTS Of the 6300 patients hospitalized, 178 were diagnosed with CDI. CDI prevalence was 2.8% (178/6300). Thirty patients were excluded from the study. The 148 cases with CDI were compared to 148 hospitalized controls. Mean body mass index (BMI) in the CDI group was 33.6 (SD, 4.3) versus 28.9 (SD, 5.4) in the control group (P = .001). The multivariable model of conditional logistic regression for matched pairs showed that a history of intra-abdominal surgery (odds ratio [OR] = 2.865; 95% confidence interval [CI], 1.26-6.52) and a high BMI value (OR = 1.196 per 1-unit increase in the BMI scale; 95% CI, 1.12-1.27) were the only variables found to be significantly associated with CDI. CONCLUSIONS Our findings suggest that obesity is associated with the risk of CDI. Further studies are needed to reveal the exact mechanisms underlying this association.