Anaemia in inflammatory bowel disease: a population-based 10-year follow-up

The point prevalence estimates of anaemia in patients with inflammatory bowel disease (IBD) range between 6% and 74%. The variation is probably due to differences in the definition of anaemia and the study populations.

To retrospectively determine the prevalence of anaemia at diagnosis and at the 1-, 5- and 10-year follow-ups in patients with IBD from a prospectively followed, population-based inception cohort (the IBSEN Study). To compare the prevalence of anaemia after a 10-year disease course with the prevalence of anaemia in the background population, and to assess clinical factors associated with anaemia at diagnosis and during follow-up.

Newly diagnosed IBD patients were included in a population-based, prospective cohort. Follow-up was performed at 1, 5 and 10 years. All visits included clinical examinations and blood samples. Anaemia was defined according to the WHO.

A total of 756 patients (UC, n = 519 and CD, n = 237) were included; 48.8% of CD and 20.2% of UC patients were anaemic at diagnosis (P < 0.001). The proportion of patients with anaemia decreased during the disease course in all patients, except in women with CD. After 10 years of disease, the relative risk for anaemia was increased in all groups, except for women with UC. The variables associated with anaemia were generally unchanged during the disease course, and elevated CRP was the strongest predictor of risk.

Anaemia was more common in CD than in UC. The prevalence of anaemia decreased during the disease course. Women with CD were at high risk for anaemia. Elevated CRP was independently associated with anaemia.