Evolution of the prevalence and characteristics of anemia in inflammatory bowel diseases between 1993 and 2003

Anemia has been considered as an overlooked complication of inflammatory bowel disease. Studies dating back to the 80ties and the 90ties have shown 30% of anemia among inflammatory bowel disease (IBD) patients. More recently, the broader use of immunosuppressive drug and infliximab allowing better mucosal healing as well as a more aggressive treatment of anemia, including the use of safer form of IV iron, may have influenced the prevalence of anemia among IBD patients. Our aim was to asses the prevalence and characteristics of anemia among two cohorts of IBD patients at 10 years interval and to look for associated clinical or demographic factors.

Using the IBD patients register of one senior gastroenterologist, we identified IBD patients he had consecutively seen and who had blood test at the outpatient clinic during the years 1993 and 2003. Demographic and clinical characteristics, treatment for Crohn's disease, blood test results and treatment of anemia were recorded and compared between these two cohorts. Anemia was defined as an hemoglobin level lower than the normal value of the laboratory of our hospital.

80 and 90 patients were identified in 1993 and 2003, respectively. There was no significant difference between the two cohorts, according to age, gender, disease type, duration or location. There were 27/80 (33.8%) and 15/90 (16.7%) anemic patients in 1993 and 2003, respectively (P = 0.013). The prevalence of severe anemia (hemoglobin level < 10.5 g/100 ml) was similar in the two cohorts (6.3% and 5.6%). Characteristics of the anemia were similar in the two cohorts with a majority of iron deficiency anemia and inflammatory anemia. Ferritin and CRP levels were not significantly different in the two cohorts. The only significant difference was a more frequent use of immunosuppressive treatment and infliximab in 2003 than in 1993 (33.3% vs. 13.8% ; P = 0.0038, RR: 0.41, 0.22-0.77)

Prevalence of mild to moderate anemia has significantly decreased in our population over the last 10 years. The only difference detected between the two cohorts was the increased use of immunosuppressive drug (mainly azathioprine).