Anti-Saccharomyces cerevisiae antibody (ASCA) positivity is associated with increased risk for early surgery in Crohn's disease.

Abstract

Anti-Saccharomyces cerevisiae antibodies (ASCA) are a specific but only moderately sensitive diagnostic marker for Crohn's disease. We sought to explore the role of ASCA as a prognostic marker for aggressive disease phenotype in Crohn's disease. To determine the role of ASCA status as a risk factor for early surgery in Crohn's disease. We performed a case control study in a cohort of patients, newly diagnosed with Crohn's disease, between 1991 and 1999. All patients were followed for at least three years. Case subjects (n = 35) included those who had major surgery for Crohn's disease within three years of diagnosis. Controls (n = 35) included patients matched to cases for age, sex, disease location, and smoking status, and who did not undergo major surgery for Crohn's disease within three years of diagnosis. Blinded assays were performed on serum for ASCA (immunoglobulin (Ig)A and IgG). A paired analysis of cases-controls was performed to test for the association between ASCA status and risk of early surgery. ASCA IgA was strongly associated with early surgery (odds ratio (OR) 8.5 (95% confidence interval (CI) 2.0-75.9); p = 0.0013). ASCA IgG+ and ASCA IgG+/IgA+ patients were also at increased risk for early surgery (OR 5.5 (95% CI 1.2-51.1), p = 0.0265; and OR 5.0 (95% CI 1.1-46.9), p = 0.0433, respectively). The association between ASCA and early surgery was evident in patients requiring surgery for ileal or ileocolonic disease. Patients with Crohn's disease who are positive for ASCA IgA, IgG, or both, may define a subset of patients with Crohn's disease at increased risk for early surgery.