Patients With Ulcerative Colitis and Primary Sclerosing Cholangitis Frequently Have Subclinical Inflammation in the Proximal Colon.

BACKGROUND & AIMS Patients with primary sclerosing cholangitis (PSC) and ulcerative colitis (UC) have a high risk of colonic neoplasia. Neoplasia frequently develops in the proximal colon in patients with PSC. Histologic inflammation is an independent risk factor for the development of neoplasia; we investigated whether patients with UC and PSC have more subclinical disease activity than patients with UC alone. METHODS We performed a retrospective analysis of data from 143 patients (205 examinations) with ulcerative pancolitis who were in clinical remission and treated at a tertiary medical center from May 2011 through May 2016. Endoscopic and histologic activity were compared between patients with PSC (from 36 examinations) and without PSC (from 169 examinations). Disease activity was scored per colonic segment using a modified Mayo endoscopic subscore and histologic assessment. In each colonic segment, differences in disease activity and the degree of discordance between endoscopic and histologic inflammation among UC patients with and without PSC were compared. RESULTS Patients with UC-PSC had significantly more subclinical endoscopic (odds ratio [OR], 4.21; 95% CI, 1.67-10.63) and histologic activity (OR, 5.13; 95% CI, 2.25-11.68) in the right colon, as well as greater degree of histologic than endoscopic inflammation in the proximal colon (OR, 3.14, 95% CI, 1.24-7.97), compared with patients without PSC. Patients with UC-PSC had significantly less histologic activity in the rectum on multivariate analysis (OR, 0.24; 95% CI, 0.08-0.72). CONCLUSIONS Patients with UC and PSC who are in clinical remission are significantly more likely to have endoscopic and histologic inflammation in the right colon than patients with UC without PSC. Our findings provide insight into cause of colorectal cancer in UC patients with PSC.