Original ArticleIncidence and phenotype at diagnosis of inflammatory bowel disease. Results in Spain of the EpiCom studyIncidencia y fenotipo al diagnóstico en la enfermedad inflamatoria intestinal. Resultados del estudio EpiCom en España
Introduction
Inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal tract of unknown etiology. High quality epidemiological studies of unselected patients are essential in order to assess the real burden of IBD. Incidence and prevalence are highly variable among different countries, with IBD being more common in industrialized than in non-industrialized countries. For adult patients, the incidence rates vary between 0.1–20.2 for CD and 0.5–31.5 per 100,000 person-years for UC.1, 2 Traditionally, North America, Scandinavia and United Kingdom are considered the areas of highest incidence. In recent years, incidence is progressively increasing in all geographic settings,1, 3, 4 but there are studies that show a change in this trend, with stabilization or decrease in areas with previously high incidence.5, 6 The reasons for this rising incidence are uncertain. An increase in disease awareness, improved access to healthcare and diagnostic procedures, or true changes in life-style and environmental factors as a consequence of the socio-economic transition from ‘developing’ to ‘developed’ in many countries could all account for some of the changes.7, 8
Population-based inception cohorts, including incident (newly diagnosed) patients, offer the most valid picture when studying the occurrence and natural course of the disease. However, due to difficulties in executing and maintaining population-based cohorts, the capability of performing this type of study is limited in most countries.9
Spain is considered a low-incidence region compared with northern European countries,5 but few recent prospective studies are available and they show variable data in terms of incidence.10, 11, 12, 13, 14, 15, 16, 17
The European Crohn's and Colitis Organization's (ECCO) Epidemiological Committee (EpiCom) study is a prospective, population-based cohort of unselected IBD patients diagnosed in 2010 within well described geographical areas, aiming to investigate if an east-west gradient exists across European countries and to identify environmental factors involved in these differences. The study was carried out in 31 centers from 22 European countries, covering a total background of 10.1 million people.2 In Spain, Vigo is the only area participating in the EpiCom study.
The aim of this study within the ECCO-EpiCom cohort was to describe the incidence of IBD in the Vigo area and the disease phenotype characteristics at diagnosis as well as to compare them with previous data available in Spain.
Section snippets
Study centers
This is an epidemiological, descriptive, prospective, population-based study developed in the Vigo area. Vigo area is located in the South-West of Galicia, in the Atlantic coast, and includes 26 municipalities. Cases were collected from hospitals included in the public health system (Complexo Hospitalario Universitario de Vigo and Hospital POVISA). Patients who belonged to Vigo area and were diagnosed in private Hospitals (mainly Hospital POVISA, Hospital Fatima and Hospital Perpetuo Socorro)
Statistical analysis
Background population at the start of the study was 579.632 inhabitants. The incidence rate (number of new cases/100,000 inhabitants) was calculated. Age-standardized annual incidence rates were obtained using the European Standard population using 10-year age groups (from 15 to 65 years), and including also a pediatric specific group and a >65 years old group. The qualitative variables are expressed as number (n) and percentage. The quantitative variables are expressed as the mean and range.
Incidence and disease phenotype characteristics of the Vigo 2010 cohort
During the study period, 106 patients were diagnosed of IBD (102 aged 15 years or older, four pediatric patients). Of them, 53 (50%) were diagnosed with CD, 47 (44.3%) with UC and 6 (5.7%) IBDU. The incident rate (per 100,000 per year) for patients aged 15 years or older was 21.4 (10.8 for CD, 9.4 for UC and 1.2 for IBDU). Including pediatric population, incidence was reduced to 18.3 (10.3 CD, 8.7 UC and 1.1 IBDU). Age-standardized incidence rates are shown in Fig. 1.
With respect to gender, 61
Discussion
The results of our study, compared with previously published data (Table 2, prospective studies), show the highest incidence rate described so far in Spain, mainly due to an increasing incidence of CD. This agrees with a recently published systematic review that reported an increasing incidence of IBD worldwide.1 Focusing in Spain, the trend of the incidence of CD shows a notable increase in the last decade.23
Comparing different geographical areas could lead to a bias in the interpretation of
Funding
This work has not received any public or private funding.
Conflict of interest
The authors declare no conflict of interest.
Acknowledgement
We thank Johan Burisch (Copenhagen), Pia Munkholm (Copenhagen) and Peter Lakatos (Budapest) for their useful comments.
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