Epidemiology of inflammatory bowel disease in the Republic of San Marino: The “EPIMICI – San Marino” study

Background: The burden of Crohn's disease (CD) and ulcerative colitis (UC) has never been estimated in the Republic of San Marino, the third smallest nation of the world. Aims: To assess the occurrence and clinical features of CD and UC in San Marino during the last 35 years. Methods: We retrospectively evaluated the prevalence, incidence, and main clinical aspects of CD and UC from 1980 to 2014, crossing data from various sources. Results: Prevalence rates (per 100,000) on December 31, were 241 for CD (263 in males and 220 in females) and 311 for UC (370 in males and 255 in females). The specific incidence of UC steadily increased from 4.6 (95% CI: 1.5–10.6) in 1980–1984 to 12.4 (95% CI: 7.6–19.1) in 2010–2014; CD incidence showed a higher proportional increase, from 1.8 (95% CI: 0.2–6.6) in 1980–1984 to 17.9 (95% CI: 12.0–25.7) in 2010–2014. The main clinical features of CD and UC (activity and location at diagnosis, extra-intestinal manifestations, disease progression overtime, therapies, and hospitalizations) were analyzed. Conclusions: This study provides the first epidemiological report on CD and UC in San Marino, showing specific traits and overall higher prevalence and incidence rates than previously reported in neighbor Areas.