Autoimmune diseases in primary sclerosing cholangitis and their first-degree relatives.

BACKGROUND AND AIMS: Primary sclerosing cholangitis (PSC) is linked to inflammatory bowel disease (IBD). However, there is limited overlap between IBD and PSC risk genes, but a stronger association between PSC and other autoimmune conditions. We aimed to assess the coexistence and familial association of autoimmune disorders in PSC, and the influence of autoimmune comorbidity on severe outcomes. APPROACH AND RESULTS: In a matched cohort study, 1378 individuals with PSC and 13,549 general population comparators and their first-degree relatives were evaluated. National registries provided data on diagnoses and outcomes (liver transplantation, hepatobiliary cancer, and liver-related death). The OR of autoimmune disease was estimated by logistic regression. The Fine and Gray competing risk regression estimated HRs for severe outcomes. The prevalence of non-IBD, non-autoimmune hepatitis, and autoimmune disease was 18% in PSC and 11% in comparators, OR: 1.77 (95% CI: 1.53-2.05). Highest odds were seen for celiac disease [OR: 4.36 (95% CI: 2.44-7.49)], sarcoidosis [OR: 2.74 (95% CI: 1.29-5.33)], diabetes type 1 [OR: 2.91 (95% CI: 2.05-4.05)], and autoimmune skin disease [OR: 2.15 (95% CI: 1.52-2.96)]. First-degree relatives of individuals with PSC had higher odds of developing IBD, autoimmune hepatitis, and any autoimmune disease than relatives of the comparators [OR: 3.25 (95% CI: 2.68-3.91); OR: 5.94 (95% CI: 2.82-12.02); OR: 1.34 (95% CI: 1.19-1.50)]. Autoimmune comorbidity in PSC was not associated with poorer outcomes [HR: 0.96 (95% CI: 0.71-1.28)]. CONCLUSIONS: Individuals with PSC and their first-degree relatives had higher odds of autoimmune disease compared to matched comparators. This finding provides validation for prior genetic discoveries at a phenotypic level. Autoimmune comorbidity did not impact severe outcomes.

Colectomy in patients with ulcerative colitis is not associated to future diagnosis of primary sclerosing cholangitis.

BACKGROUND: Primary Sclerosing Cholangitis (PSC) is a hepatobiliary disease closely related to ulcerative colitis (UC). In PSC patients, colectomy has been linked to improved prognosis, especially following liver transplantation. This suggests an involvement of the gut-liver axis in PSC etiology. OBJECTIVE: We aimed to investigate the association between colectomy and the risk of future PSC in an epidemiological setting. METHOD: Through nationwide registers, we identified all adults diagnosed with UC in Sweden 1990-2018 and retrieved information on PSC diagnosis and colectomy. Within the UC cohort (n = 61,993 patients), we matched 5577 patients with colectomy to 15,078 without colectomy. Matching criteria were sex, age at UC onset (±5 years), year of UC onset (±3 years), and proctitis at the time of colectomy. Incidence rates of PSC per 1000-person year were calculated, and the Cox proportional hazard regression model estimated hazard ratios (HRs) for PSC until 31 December 2019. RESULTS: During the follow-up, 190 (3.4%) colectomized UC patients and 450 (3.0%) UC comparators developed PSC, yielding incidence rates of 2.6 and 2.4 per 1000 person-years (HR 1.07 [95% CI 0.90-1.28]). The cumulative incidence of colectomy decreased remarkably over calendar periods, but the cumulative incidence of PSC remained unchanged. The risk of developing PSC in colectomized versus comparators changed over time (HR 0.68 [95% CI; 0.48-0.96] in 1990-97 and HR 2.10 [95% CI; 1.37-3.24] in 2011-18). CONCLUSIONS: In UC patients, colectomy was not associated with a decreased risk of subsequent PSC. The observed differences in the risk of PSC development over calendar periods are likely due to changes in PSC-diagnosis and UC-treatment.

Increased risk of cancer in patients with primary sclerosing cholangitis.

BACKGROUND AND AIMS: Primary sclerosing cholangitis (PSC) is associated with an increased risk of hepatobiliary and colorectal cancer, but the risks of other cancer forms have not been explored. The aim of this study was to evaluate the risk of intestinal and extraintestinal cancers in a large, well-defined cohort of PSC patients. MATERIAL AND METHOD: A matched cohort study of Swedish PSC patients was performed with up to ten comparators for each patient, matched for sex, age, and residency. The data were retrieved from national registers. Patients were followed from PSC diagnosis until cancer diagnosis, liver transplantation, first emigration date, death, or December 31, 2016. The risk of cancer was estimated using the Kaplan-Meier method and Cox regression models. RESULTS: In total, 1432 PSC patients with a verified diagnosis and 14,437 comparators were studied. The mean follow-up time was 15.9 years. Eighty-eight percent of the PSC patients had concomitant inflammatory bowel disease. PSC patients ran significantly increased risks of developing any cancer [HR 3.8, 95% confidence interval (CI) 3.3-4.3], hepatobiliary cancer (HR 120.9, 95% CI 72.0-203.1), colorectal cancer (HR 7.5, 95% CI 5.6-10.0), pancreatic cancer (HR 8.0, 95% CI 3.2-20.2), gastric cancer (HR 4.2, 95% CI 1.5-11.3), small bowel cancer (HR 21.1, 95% CI 3.5-128.2), and lymphoma (HR 3.0, 95% CI 1.6-5.7). PSC was not associated with a lower risk of any cancer form. CONCLUSIONS: PSC patients have a four times overall increased risk of developing cancer compared to the general population, with increased risk of developing hepatobiliary, colorectal, and pancreatic cancer, as well as lymphoma.