Clinical Outcomes and Long-Term Prognosis of Perianal Crohn's Disease in an Asian population.

BACKGROUND AND AIM The clinical impact of perianal Crohn's disease (pCD), a well-known poor prognostic factor of Crohn's disease (CD), has not been fully evaluated in Asian patients. We investigated the outcomes of CD in Korean patients according to the presence of pCD at CD diagnosis. METHODS Using 2010-2014 data from the national health insurance claims database, we evaluated the disease course of CD according to the presence of pCD at CD diagnosis. The results were verified in a hospital-based cohort of 2923 patients. RESULTS The cumulative risk of intestinal resection was lower in patients with pCD at diagnosis than in those without, in the population-based cohort (9.1% vs. 14.7% at five years after diagnosis, P<0.001), but it was similar between the two groups in the hospital-based cohort (36.8% vs. 36.8% at 10 years after diagnosis, P=0.950). Moreover, the cumulative risk of behavioral progression was not significantly different between the two groups in the hospital-based cohort (43.4% vs. 41.6% at 10 years after diagnosis, P=0.366). On multivariable analysis, pCD at CD diagnosis was not a predictor of intestinal resection, behavioral progression, CD-related hospital admission, or diverting surgery; however, it was an independent predictor of proctectomy (hazard ratio [HR] 3.210, P<0.001) and anorectal cancer (HR 3.104, P=0.047). CONCLUSIONS Although the presence of pCD increased the risk of proctectomy and anorectal cancer in Asian patients, the clinical impact of pCD on the overall outcomes of patients with CD may be less significant in Asian patients compared to Western patients.