Abstract Background There is a recent trend of change in the epidemiology of these diseases with increasing incidence in areas with low incidence, while in Western Europe and North America the incidence is somewhat stable. Considering that there had been no previous published epidemiological data on IBD for Bulgaria, the aim of this study was to obtain and describe epidemiological data of IBD in an adult population in the northeastern, north-central, and southeastern regions of Bulgaria. Methods A total of 722 IBD patients over the age of 18 years were included in the study. They were treated at Referral IBD Center—at the University Multiprofile Hospital for Active Treatment “St. Marina” in Varna, Bulgaria, during the period 2013-2022. All patients included in the study fulfilled IBD criteria according to the guidelines of the European Crohn’s and Colitis Organization. It is a descriptive, retrospective, hospital-based epidemiological study conducted at a large university referral IBD center in northeastern Bulgaria. All data about medical history, number of hospitalizations, and demographic characteristics, was extracted from the hospital’s digital patient records. Demographic information for the population over 18 years old in the studied region between 2013 and 2022 was based on data published by the Bulgarian National Statistical Institute. Results The mean crude prevalance of IBD for 10 years period was 6.42/100000 inhabitants (95%CI: 5.54, 7.30). In the male population 10 years crude prevalance was 1.32/100000 inhabitants (95%CI: 0.98, 1.66) and 1.33/100000 inhabitants (95%CI: 0.99, 1.67) in the female population (p 0.005). The crude average annual prevalence in urban areas is 6.45 per 100,000 people (95% CI: 5.55–7.35). In rural areas, the average annual prevalence is 4.69 per 100,000 people (95% CI: 3.59–5.79). Newly diagnosed IBD cases are 191 (26.5%) for the study period. The crude average annual incidence for the period 2013–2022 is 0.72 cases per 100,000 people (95% CI: 0.52–0.92). There was not statistically significant variation in incidence rates was observed across the years (p 0.05). Among men, the crude average annual incidence is 0.83 cases per 100,000 people (95% CI: 0.69–0.97). The crude average annual incidence among women is 0.59 cases per 100,000 people (95% CI: 0.39–0.79), (p 0.055). There was no statistically significant difference in IBD incidence rates between males and females, based on the standard 95% confidence interval (p 0.05). Conclusion This study provides preliminary data on the epidemiology of IBD in Bulgaria. A more extensive epidemiological investigation is necessary, as the current study is limited to patients who attended the referral center, meaning it does not cover all cases of IBD in the region. References: 1. Burisch J, Pedersen N, Cukovic-Cavka S, Brinar M, Kaimakliotis I, Duricova, et al. Eastwest gradient in the incidence of inflammatory bowel disease in Europe: the ECCOEpiCom inception cohort. Gut 2013;2:1–10. 2. Lakatos PL. Recent trends in the epidemiology of inflammatory bowel diseases: up or down? World J Gastroenterol. 2006 Oct 14;12(38):6102-8. doi: 10.3748/wjg.v12.i38.6102. PMID: 17036379; PMCID: PMC4088101. 3. Lovasz BD, Golovics PA, Vegh Z, Lakatos PL. New trends in inflammatory bowel disease epidemiology and disease course in Eastern Europe. Dig Liver Dis 2013;45:269–76. Conflict of interest: Georgieva, Avgustina Chavdarova: None Atanassova, Antonia: No
Georgieva et al. (Thu,) studied this question.