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PREDICTIVE FACTORS ASSOCIATED WITH IMMUNOSUPPRESSIVE AGENT USE IN ULCERATIVE COLITIS: A CASE-CONTROL STUDY

A Lau, J Gregor
University of Western Ontario, London Health Sciences Centre, Department of Medicine, London, Ontario

BACKGROUND: Ulcerative colitis (UC) represents a spectrum of disease varying from proctitis to pancolitis and from mild to fulminent colitis. Medical therapies range from topical to systemic therapies, from 5-aminosalicylic acids to steroids or immunosuppressants or immunomodulants. Factors predisposed to or associated with the use of immunosuppressants in UC were not well described. We aimed to study the epidemiological, social and familial factors, as well as the severity and the extensiveness of the disease on diagnosis that might predict the requirement for immunosuppressants as maintenance therapy in UC.
METHODS: All UC patients diagnosed between 1992 and 2005 and are currently managed in the IBD clinic at the South Street Hospital were included in the study. 43 of them are currently on or had been on Azathioprine or 6-MP for UC versus 130 of them who are immunosuppressant-naive (matched controls). Clinic and hospital charts were reviewed and potential predictive factors were registered. Logistic regression analysis, with univariate and multivariate analyses were applied to identify factors associated with Azathioprine and 6-MP use.
RESULTS: In the univariate model, the most important factors associated with immunosuppressant use were male gender (OR 2.2; 95% CI: 1.1-4.5), more than 4 bowel movements a day on diagnosis (OR 2.1; 95% CI: 0.6-7.1), persistent or mostly blood in the stool on diagnosis (OR 2.8; 95% CI: 1.1-7.3), requirement of hospitalization on diagnosis (OR 2.7; 95% CI: 1.2-6.1), extensive colitis or pancolitis on diagnosis (OR 3.9; 95% CI: 1.9-8.1), moderate to severe disease on UC activity index on diagnosis (OR 7.2; 95% CI: 2.0-25.9) and systemic steroid use within the first 6 months of diagnosis (OR 5.1; 95% CI: 2.3-11.2). Age of diagnosis, smoking status and family history of IBD were not statistically significant. Because of the small study sample size, only systemic steroid use was found to have statistical significance on multivariate model.
CONCLUSIONS: These results suggest that male gender, initial presentation with moderate to severe symptoms, endoscopically proven extensive colitis, requirement of hospitalization or systemic steroids within 6 months of diagnosis are all predictive factors for the requirement of immunosuppressants as maintenance therapy in UC.

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