Burden of disease and increasing prevalence of inflammatory bowel disease in a population-based cohort in the Netherlands.

BACKGROUND: Reported epidemiology and phenotype distributions vary widely and disease burden of inflammatory bowel disease (IBD) is poorly described. Our aim was to establish these features in a population-based cohort covering 319 976 inhabitants. Furthermore, differences between tertiary referral and peripheral hospital patients were quantified. METHODS: IBD patients in the adherence area of three peripheral hospitals (2004-2012) were included. Medical and surgical treatment data were obtained. Quality of life and disease activity were evaluated. An outpatient cohort from a tertiary referral centre was accrued. RESULTS: A total of 1461 patients were included: 761 (52.1%) with ulcerative colitis (UC), 579 (39.5%) with Crohn's disease (CD) and 121 (8.3%) with IBD-unspecified. Point prevalence of IBD was 432.1 per 100 000 inhabitants in 2010, which increased significantly over time, P-value of less than 0.0001. The mean annual incidence was 17.2 for UC, 10.5 for CD and 2.2 for IBD-unspecified. Tertiary referral Crohn's patients used thiopurines and biological therapy and underwent surgery significantly more often than patients in peripheral hospitals (P<0.0001). Disease activity correlated negatively with quality of life (P<0.0001) in UC and CD. CONCLUSION: The prevalence of IBD is still increasing. Burden of disease was significantly more severe, mainly in Crohn's patients, in the referral centre, highlighting the importance of population-based studies to accurately describe phenotype distribution and disease burden.

Risk factors for primary sclerosing cholangitis.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) is a progressive cholestatic liver disease of unknown cause, but strongly associated with inflammatory bowel disease (IBD). Potential risk factors triggering PSC have never been studied on a population level. The aim of this study was to evaluate smoking, appendectomy, family history and geographical distribution in a population-based cohort of PSC patients, as compared to IBD control patients and healthy controls (HC). METHODS: For this case-control study 343 PSC patients, 370 IBD controls and 232 HC's living in a geographically defined area in the Netherlands filled-out a questionnaire concerning smoking, appendectomy and family history of IBD and autoimmune liver diseases. RESULTS: Smoking was associated with a lower risk of developing PSC in PSC-ulcerative colitis (UC) patients (adjusted OR 0.21; 95% CI 0.12-0.34; P < 0.001). Comparable results were found for PSC-Crohn's disease (CD) patients (16% former smokers) compared to CD patients (55% former smokers) (adjusted OR 0.17; 95% CI 0.08-0.39; P < 0.001). Frequency of appendectomy did not differ between PSC and HC, but PSC-UC patients had undergone appendectomy more often than UC patients (13% vs. 6%) (adjusted OR 2.51; 95%CI 1.04-6.07; P = 0.041). We found no association between family history of IBD or autoimmune liver disease and risk of PSC. Degree of urbanization was not associated with PSC incidence. CONCLUSION: In this large population-based case-control study we confirm that smoking is associated with a lower risk of developing PSC, independent of its protective effect for developing UC. Appendectomy is not associated with the risk of developing PSC.

Population-based epidemiology, malignancy risk, and outcome of primary sclerosing cholangitis.

UNLABELLED: Extensive population-based studies are much needed to accurately establish epidemiology and disease course in patients with primary sclerosing cholangitis (PSC). We aimed to obtain population-based prevalence and incidence figures, insight in disease course with regard to survival, liver transplantation (LT), and occurrence of malignancies, as well as risk factors thereof. Four independent hospital databases were searched in 44 hospitals in a large geographically defined area of the Netherlands, comprising 50% of the population. In addition, all PSC patients in the three Dutch liver transplant centers and all inflammatory bowel disease (IBD) patients in the adherence area of a large district hospital were identified. All medical records were reviewed on-site, verifying diagnosis. Five hundred and ninety PSC patients were identified, resulting in an incidence of 0.5 and a point prevalence of 6.0 per 100,000. Median follow up was 92 months. Estimated median survival from diagnosis until LT or PSC-related death in the entire cohort was 21.3 years, as opposed to 13.2 years in the combined transplant centers cohort (n = 422; P < 0.0001). Colorectal carcinoma (CRC) risk was 10-fold increased, as compared to ulcerative colitis controls, and developed at a much younger age (39 years; range, 26-64), compared to IBD controls (59 years; range, 34-73; P = 0.019). Colonoscopic surveillance was associated with significantly better outcome. CONCLUSION: This study exemplifies that, for relatively rare diseases, it is paramount to collect observational data from large, population-based cohorts, because incidence and prevalence rates of PSC are markedly lower and survival much longer than previously reported. The selection of a bias-free, population-based cohort showed a significantly longer survival, compared to the tertiary referral cohort. CRC can develop at an early age, warranting surveillance from time of PSC diagnosis.