Mo1833 Clinical Characteristics of Crohn's Disease and Ulcerative Colitis Patients Who Switched From an anti-TNF-α Agent or Natalizumab to Vedolizumab or an Alternative anti-TNF-α

was carried out in two hospitals in the south of Spain.The databases of the two hospitals were reviewed over two periods of time (from 1995 to 2000 and from 2001 to 2014) and were compared.The following variables were tested: age, sex, smoking, localization of disease at diagnosis and family history of IBD and were compared between the two periods of time.Inclusion criteria were age more than 14 years old and a clinical diagnosis of IBD.Results: The population of both hospitals was 1.011.555habitants and a total of 2519 patients were collected.In the first period, 430 patients were registered.The total incidence rate was 7,07 per 100,000 person-years.Ulcerative Colitis (UC) incidence was 3,57 per 100,000 personyears and Crohn Disease (CD) incidence was 3,50 per 100,000 person-years.UC was diagnosed in 50,4%(n=217).In the second period, 2089 patients were registered.The incidence of IBD was 14.7 per 100,000 person-years.The incidence of UC was 7.6 per 100,000 person-years and 7.1 cases per 100,000 person-years for CD patients.UC was diagnosed in 51.7% (n=1081) Epidemiological data are shown in Image1.Comparing both periods of time, the incidence has doubled with statistically significant differences: Image2.Regarding the epidemiological data, statistically significant differences between both periods was found in the following variables: age, family history of IBD and localization of UC at diagnosis (p <0.05).Conclusions The incidence of IBD in the south of Spain has dramatically increased in the last two decades and it is similar to the data reported in other European countries.Some differences have been found between the two periods (age at diagnosis, family history and localization).Due to the fact that it is a retrospective study, selection bias cannot be ruled out.