Risk factors and clinical courses of concomitant primary sclerosing cholangitis and ulcerative colitis: a Korean multicenter study

Background: Primary sclerosing cholangitis (PSC) is a rare progressive cholestatic liver disease of unknown causes, but is strongly associated with inflammatory bowel diseases (IBDs), particularly ulcerative colitis (UC). However, studies comparing risk factors and clinical courses of patients with concomitant UC and PSC with those of patients with PSC alone are lacking. Methods: We retrospectively reviewed patients with PSC diagnosed between 2005 and 2017 in four tertiary hospitals in Korea. We compared the risk factors and outcomes of concomitant UC and PSC (UC-PSC) and those of PSC alone. Results: PSC was diagnosed in 50 patients in four different tertiary hospitals in Korea. Of them, 18 patients (36.0%) had UC-PSC and 32 patients (64.0%) had PSC alone. The median age at PSC diagnosis was younger in the UC-PSC group than that in the PSC alone group (37 vs. 54 years, P = 0.002). In multivariate analysis, older age at PSC diagnosis (P = 0.007; odds ratio [OR], 0.884; 95% confidence interval [CI], 0.808–0.966) and current smoking habit (P = 0.033; OR, 0.026; 95% CI, 0.001–0.748) were determined to be independent factors for reducing the possibility of developing concomitant UC after PSC. Additionally, UC-PSC was shown to be an independent risk factor for the development of colorectal dysplasia (P = 0.044; OR, 10.829; 95% CI, 1.065–110.127). Conclusions: Our analysis showed that UC-PSC is more likely to be negatively associated with current smoking and older age at the time of PSC diagnosis. Moreover, UC-PSC increased the risk of colorectal dysplasia.