Does Obesity Influence the Risk of Clostridium difficile Infection Among Patients with Ulcerative Colitis?

Patients with ulcerative colitis (UC) are at an increased risk of Clostridium difficile infection (CDI) compared with the general population. Recent data suggest that obesity also increases the risk of CDI.

To examine whether obesity influences the risk of CDI among patients with UC.

We conducted a retrospective cross-sectional study of UC patients seen in gastroenterology clinic between January 1, 2014, and December 31, 2015. Records were reviewed for patients with the diagnosis of UC prior to 2014, and the first diagnosis of CDI between January 1, 2014, and December 31, 2015. Using body mass index (BMI), patients were classified into underweight (BMI < 18.5), normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). Age-adjusted and multivariate logistic regression was performed including gender, tobacco use, UC disease duration, medication exposure, and vitamin D deficiency.

Of the 636 patients with UC, 114 (18%) were obese, 232 (36%) overweight, 274 (43%) normal weight, and 16 (2.5%) underweight. Nineteen patients (3.0%) developed CDI during the study period. CDI risk was not associated with BMI (OR 0.90, 95% CI 0.79-1.02). Compared to normal weight patients, risk of CDI was not influenced by being obese (multivariate OR 0.63, 95% CI 0.15-2.58), overweight (multivariate OR 0.33, 95% CI 0.08-1.30), or underweight (multivariate OR 2.98, 95% CI 0.45-19.83). CDI was associated with ever use of TNF therapy (multivariate OR 6.09, 95% CI 2.07-17.93) but not vedolizumab (multivariate OR 0.76, 95% CI 0.08-7.36).

Obesity does not appear to be associated with the risk of C. difficile infection among patients with UC.