Time trends in the epidemiology and outcome of perianal fistulizing Crohn's disease in a population-based cohort

Perianal disease is a debilitating condition that frequently occurs in Crohn's disease (CD) patients. It is currently unknown whether its incidence has changed in the era of frequent immunomodulator use and biological availability. We studied the incidence and outcome of perianal and rectovaginal fistulas over the past two decades in our population-based Inflammatory Bowel Disease South-Limburg cohort. All 1162 CD patients registered in the Inflammatory Bowel Disease South-Limburg registry were included. The cumulative probabilities of developing a perianal and rectovaginal fistula were compared between three eras distinguished by the year of CD diagnosis: 1991-1998, 1999-2005 and 2006-2011. Second, clinical risk factors and the risk of fistula recurrence were determined. The cumulative 5-year perianal fistula rate was 14.1% in the 1991-1998 era, 10.4% in the 1999-2005 era and 10.3% in the 2006-2011 era, P=0.70. Colonic disease was associated with an increased risk of developing perianal disease, whereas older age was associated with a decreased risk (both P