Long‐term course of Crohn's disease in Japan: Incidence of complications, cumulative rate of initial surgery, and risk factors at diagnosis for initial surgery

Background and Aims: Intestinal complications of stenosisor fistula may occur during the course of Crohn's disease (CD), and surgeryis performed in a fair number of patients. The risk factors for initial surgeryin a Japanese hospital-based cohort of CD patients were evaluated. Methods: This study was a single-center, retrospective, cohort study. The subjects were 520 patients who underwent inpatient and outpatient treatment at our hospital, had a definitive diagnosis of CD, and no previous surgery. Three parameters were investigated: (i) cumulative incidenceof stenosisand fistula; (ii) cumulativerate of initial surgeryfor each disease type; and (iii) risk factors at diagnosis for initial surgery. Results: (i) Stenosisand fistula increased with time, with stenosisor fistula appearing in about half of the patients after 5 years. (ii) The cumulativerate of initial surgerywas about 50% after 10 years. (iii) The patient factors at diagnosis of current smoker, upper gastrointestinal disease, stricturing, penetrating, moderate to severe stenosisof the jejunum, moderate to severe stenosisof the ileum, and moderate to severe stenosisof the terminal ileumwere risk factors for initial surgery. Conclusions: Stenosisor fistula appeared in about half of the patients after 5 years from diagnosis. When upper gastrointestinal disease or complicated small intestinal lesions are seen at the time of diagnosis, the cumulativerate of initial surgeryis significantly higher.