Prevalence and predictors of severe Crohn's disease at a tertiary hospital in South Africa.

Background Predicting severe Crohn's disease (SCD) can assist in planning risk reduction therapy for SCD, thereby improving disease outcomes. Objective To determine the prevalence and predictors of SCD in a sample of South African patients. Methods This was a retrospective chart review of patients with Crohn's disease (CD) attending the Gastroenterology Unit at a tertiary hospital in Durban, South Africa. Demographic and clinical variables at diagnosis of CD were collected and analysed for statistical association with development of SCD (defined as the presence of >/= 1 of the following over the course of CD: complex perianal disease, colonic resection >/= 2 small bowel resections, a single small bowel resection > 50cm, or construction of a definitive stoma). The prognostic utility of statistically significant variables was investigated by establishing their sensitivity, specificity, and predictive values for SCD.  Results The study consisted of 93 patients. The rate of SCD was 64.5%, with 63.3 % of patients developing SCD within 1 year of CD diagnosis. Ileocolonic location (p = 0.046) and penetrating disease at initial diagnosis of CD (p = 0.021) were statistically associated with SCD. The sensitivity, specificity, positive predictive value, and negative predictive value of ileocolonic location for SCD was 72.7%, 47.4%, 66.7% and 54.6%. The sensitivity, specificity, positive predictive value, and negative predictive value of penetrating disease for SCD was 85.7%, 41.7%, 30.0% and 91.0%. Conclusion Most patients with CD developed SCD within 1 year of their CD diagnosis. CD with a penetrating phenotype at diagnosis is a good predictor for the devleopment of SCD and should be further investigated.