Younger Age at Diagnosis Predicts Disease Severity in Ulcerative Colitis

Abstract

Purpose: Canada has one of the highest incidences of ulcerative colitis (UC) in the world, with 3500 new cases each year and a prevalence of over 60, 000†. Previous studies have examined the natural history of UC, however, this is the first to examine it in Southwestern Ontario (SWO). London is uniquely situated with a catchment area of nearly all of SWO, and the London Health Sciences Centre – South Street Hospital (LHSC-SSH) Inflammatory Bowel Disease (IBD) clinic is set up to longitudinally follow patients who are diagnosed and treated there. The goal of the current study is to understand the demographic characteristics of this population in order to predict disease severity. †Am J Gastro 2006;101:1559–68. Methods: Records from 1996 to 2001 were examined to create a database of UC patients seen in the LHSC-SSH IBD clinic. To be included, patients’ charts were required to have information of their disease presentation and a minimum of five years of follow-up. Charts were reviewed using standardized data collection forms. Disease severity was generated during the chart review process, and non-endoscopic Mayo Severity Index‡ criteria were collected into a composite. ‡NEJM 1987;317:1625–9. Results: 102 consecutive patients’ data were entered into the database. Demographic analyses revealed that 51% of the patients were male, the mean age at diagnosis was 39 years, 13.7% had a first degree relative with IBD, 61.8% were nonsmokers and 24.5% were ex-smokers. In 22.5% of patients the disease was limited to proctitis, 21.6% had proctosigmoiditis, 22.5% had left-sided colitis, and 32.4% had pancolitis. Standard multiple regression analysis which regressed a composite of physician global assessment of disease severity, average number of bowel movements, and average amount of blood in bowel movements on year of diagnosis and age at time of diagnosis was significant, R2 = .306, F (7, 74) = 4.66, P < .01. Delay from symptoms to diagnosis of UC, gender, family history of IBD, smoking status and disease severity at the time of diagnosis did not significantly predict the composite measure. Conclusion: A composite of UC disease severity, blood in bowel movements, and number of bowel movements is associated with younger age at diagnosis as well as year of diagnosis in a longitudinal cohort of UC patients in SWO. This suggests a potential mechanism for predicting disease severity at diagnosis and may be a step towards the identification of prognostic indicators of UC.