Temporal trends in non-stricturing and non-penetrating behaviour at diagnosis of Crohn's disease in Örebro, Sweden: a population-based retrospective study

Background and aim: The incidence of Crohn's disease (CD) is continuing to rise in several countries and in others it appears to have already levelled off after a period of increase. We updated our previous population-based study, by re-extraction of all information on patients diagnosed with CD between 1963 and 2010. Our aim was to assess temporal trends in incidence, prevalence and disease phenotype at diagnosis.

Methods: Patients of all ages with a potential diagnosis of CD were identified retrospectively by evaluation of medical notes of all current and previous patients at the colitis clinic, Örebro University Hospital amended by computerised search in the inpatient, outpatient, primary care and histopathological records. Diagnosis was confirmed by subsequent evaluation of medical notes. Disease phenotype was defined according to the Montreal classification.

Results: The incidence increased over time, especially among Crohn's disease, A1 and A3. SaTScan model revealed a statistically significant high incidence during 1991-2010 (p=0.0001). The median age at diagnosis increased from 28 (3-79) years to 37 (5-87) years (p=0.0002). The point prevalence increased from 21/10(5) (14-32) in 1965 to 267/10(5) (244-291) in 2010. Non-stricturing and non-penetrating disease at diagnosis increased from 12.5% in 1963-1965 to 82.3% in 2006-2010 (p<0.0001).

Conclusion: The incidence of CD increased over time, although it seemed to be plateauing during the most recent decades. A striking increase in non-stricturing, non-penetrating disease at diagnosis was observed, suggesting earlier diagnosis or phenotypic change. The observed point prevalence in 2010 is among the highest reported.