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Is the epidemiology of inflammatory bowel disease changing in Eastern Europe?

To the Editor: We read with interest the article by Mijandrusic-Sincic et al. [1] describing the population-based survey on the epidemiology of inflammatory bowel diseases (IBD) in Croatia. Previous studies conducted in Europe suggested that the incidence of IBD was decreasing in a north to south gradient, yet in the early 1990s, the European IBD Study Group found comparable rates between Southern and Northern Europe [2]. Until recently, only limited data were available on the epidemiology of IBD in Eastern Europe. In a prospective design, the investigators revealed an incidence for Crohn’s disease (CD) of 7.0 (100 patients) and that for ulcerative colitis (UC) of 4.3 (70 patients) for the period 2000 04. The data were based solely on the records of a single hospital; both inand outpatient data of the Departments of Gastroenterology, Surgery, and Paediatric and Infectious Diseases were collected. No systematic search for other patients was conducted, nor were general practitioners contacted, thus the incidence may have been underestimated. Notwithstanding, a much higher incidence rate was reported compared with that in an earlier study from Zagreb, by Vucelic et al., showing an incidence of 0.7/for CD and 1.5/10 for UC. What is even more interesting is that the prevalence of CD has increased in comparison with UC. These data suggest a change other than better case ascertainment by more up-to-date diagnostic procedures in the epidemiology of IBD in Eastern Europe. The same trend was observed in Hungary in a population-based, partly prospective study performed by our group [3]. We reported an increase in the incidence of UC from 1.6 to 11.0 and for CD from 0.4 to 4.7 between the years 1977 and 2001. The prevalence rate was 142.6 for UC and 52.9 for CD in 2001, which is comparable with the rates in West European countries. Differences were also noted between East and West Hungary, as the incidences although the trend was similar tended to be lower for both UC and CD in the study by Nagy et al. (CD: 0.43 3.1, UC: 1.0 3.6) conducted between 1962 and 1992. However, this later study was also hospital based [4]. In contrast, other countries (e.g. the Czech Republic, Poland, Romania, Slovakia and the Baltic countries) still reported low incidence and prevalence rates. A single hospital-based observational case series, originating in Poland, was published in 2005. Based on the published data, the average incidence of UC can be estimated at around 1.8/ 10, and that of CD at 0.1/10 [5]. The trends, however, indicate an increasing incidence also in some of the low-prevalence areas. An increased incidence of both UC (from 0.5 to 1.5) and CD (from 0.3 to 1.5) was reported in children and adolescents in a prospective, population-based survey during the 1990s in Moravia, the Czech Republic. In addition, the discrepancy between the incidence and prevalence values published in the single multicentre study from Romania may indicate an increasing prevalence [6]. The reported incidence was 0.97/10 for UC and 0.50/10 for CD, while the corresponding prevalence rates were 2.25/ 10 for UC and 1.51/10 for CD. However, the data were collected through self-reporting by the gastroenterology centres; thus the low prevalence rate might have partly been a consequence of the limitations in methodology. The increased incidence of both UC and CD observed in Croatia and Hungary raises further