Abstract Background There is currently no comprehensive epidemiological data on inflammatory bowel disease (IBD) in Bulgaria. This retrospective study aims to analyze the epidemiological characteristics of IBD over a 10-year period in Northeastern, North-Central, and Southeastern regions of Bulgaria. Methods This is a descriptive, retrospective, hospital-based epidemiological study conducted at a tertiary IBD center. The analysis includes 722 adult patients (aged ≥18 years) diagnosed with ulcerative colitis or Crohn’s disease. Results Northeastern region The mean annual crude incidence of IBD in the Northeastern region was 1. 72/ 100, 000 (95% CI: 0. 87–2. 57). Between 2013 and 2022, the mean annual crude prevalence was 13. 86/ 100, 000 (95% CI: 13. 62–14. 10). Throughout the study period, the mean annual crude prevalence in urban areas was 15. 08/ 100, 000 (95% CI: 12. 17–17. 99), compared to 10. 49/ 100, 000 (95% CI: 6. 53–14. 46) in rural areas. Northcentral region The mean annual crude incidence of IBD was estimated at 0. 41/ 00, 000 (95% CI: 0. 28–0. 54). During the period 2013–2022, the mean annual crude prevalence of IBD was 3. 12/ 100, 000 (95% CI: 1. 87–4. 37). A statistically significant upward trend was observed over time, with mean annual increase of 0. 24/ 100, 000. In urban areas, the mean annual crude incidence was 0. 43/ 100, 000 (95% CI: 0. 25–0. 61), while in rural areas it was 0. 31/ 100, 000 (95% CI: 0. 10–0. 52). Southeastern region The mean annual crude incidence of IBD in Souteastern region was 0. 15/ 100, 000 (95% CI: 0. 012–0. 288). Between 2013 and 2022, the observed annual prevalence ranged from 0. 95 to 1. 90/ 100, 000, with a mean annual value of 1. 41/ 100, 000 (95% CI: 0. 68–2. 14). In urban populations, the crude prevalence of IBD showed a clear upward trend over the study period, with a mean annual rate of 1. 85/ 100, 000 (95% CI: 1. 71–2. 37). In contrast, the prevalence among rural populations remained extremely low throughout the entire period. The mean annual crude prevalence of IBD among males was 1. 31/ 100, 000 (95% CI: 0. 99–1. 63), while among females it was slightly higher at 1. 46/ 100, 000 (n = 77, N = 5, 254, 517; 95% CI: 1. 14–1. 79). Conclusion The findings of this study support the global trend of increasing incidence of inflammatory bowel disease. For the first time in Bulgaria, the epidemiology of IBD has been systematically analyzed across three major regions—Northeastern, North-Central, and Southeastern—revealing notable regional disparities in incidence and prevalence rates. These results provide a valuable foundation for future research, including nationwide epidemiological mapping. References: 1. Caron B, Honap S, Peyrin-Biroulet L. Epidemiology of Inflammatory Bowel Disease across the Ages in the Era of Advanced Therapies. J Crohns Colitis. 2024 Oct 30;18 (Supplement₂): ii3-ii15. doi: 10. 1093/ecco-jcc/jjae082. PMID: 39475082; PMCID: PMC11522978. 2. 2. Mak WY, Zhao M, Ng SC, Burisch J. The epidemiology of inflammatory bowel disease: East meets west. Journal of gastroenterology and hepatology. 2020 Mar;35 (3): 380-9. Conflict of interest: Dr. Georgieva, Avgustina Chavdarova: No conflict of interest Atanassova, Antonia: No conflict of interest
Georgieva et al. (2026) studied this question.