Ulcerative Colitis Patients With Clostridium difficile are at Increased Risk of Death, Colectomy, and Postoperative Complications: A Population-Based Inception Cohort Study

Objectives: Clostridium difficile(C. difficile) may worsen the prognosis of ulcerative colitis (UC). The objectives of this study were to: (i) validate the International Classification of Diseases-10 (ICD-10) code forC. difficile; (ii) determine the risk ofC. difficileinfection after diagnosis of UC; (iii) evaluate the effect ofC. difficileinfection on the risk of colectomy; and (iv) assess the association betweenC. difficileand postoperative complications. Methods: The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated by comparing ICD-10 codes forC. difficilewith stool toxin tests. A population-based surveillance cohort of newly diagnosed UC patients living in Alberta, Canada were identified from 2003 to 2009 (n=1,754). The effect of aC. difficileinfection on colectomy was modeled using competing risk survival regression after adjusting for covariates. The effect of aC. difficileinfection on postoperative complications was assessed using a mixed effects logistic regression model. Results: The sensitivity, specificity, PPV, and NPV of the ICD-10 code forC. difficilewere 82.1%, 99.4%, 88.4%, and 99.1%, respectively. The risk ofC. difficileinfection within 5 years of diagnosis with UC was 3.4% (95% confidence interval (CI): 2.5–4.6%). The risk of colectomy was higher among UC patients diagnosed withC. difficile(sub-hazard ratio (sHR)=2.36; 95% CI: 1.47–3.80).C. difficileincreased the risk of postoperative complications (odds ratio=4.84; 95% CI: 1.28–18.35).C. difficilewas associated with mortality (sHR=2.56 times; 95% CI: 1.28–5.10). Conclusions: C. difficilediagnosis worsens the prognosis of newly diagnosed patients with UC by increasing the risk of colectomy, postoperative complications, and death.