Patients with large-duct primary sclerosing cholangitis and Crohn's disease have a better outcome than those with ulcerative colitis, or without IBD.

Background: Approximately 20% of primary sclerosing cholangitis (PSC) patients with concomitant inflammatory bowel disease (IBD) have Crohn's disease (CD).

Aim: To compare PSC/CD with other PSC patients.

Methods: Retrospective study of 240 PSC patients diagnosed between 1975 and 2012 (median follow-up 12 years). Activity of PSC at diagnosis was assessed by liver biopsy, Mayo risk and ERC scores. Survival without liver transplantation, number of transplantations and liver-related death were endpoints.

Results: Sixty-three per cent of patients had IBD: 105 UC, 32 CD and 14 IBD unclassified (IBDu). IBD was diagnosed before PSC in 50%. The yearly development of PSC after diagnosing IBD was similar in UC, CD or IBDu. Small-duct PSC was present in 28% of PSC/CD compared to 3% of PSC/UC. Small-duct PSC had a markedly better survival than large-duct PSC: no patient developed cholangiocarcinoma or liver-related death, but colorectal cancer occurred in three patients. In large-duct PSC, a more favourable outcome was evident in patients with CD. The liver disease was less progressive: one patient underwent liver transplantation compared to 28% and liver-related deaths were absent compared to 7% in the other PSC groups.

Conclusions: The prevalence of PSC with concomitant Crohn's disease is relatively rare, but the outcome is more benign than PSC with UC or without IBD. Approximately one-fourth has small-duct PSC. In large-duct PSC/CD, liver disease is less aggressive and the outcome is much better. The outcome of PSC patients with UC resembled that of PSC without IBD.