In a study reported in the April 2004 issue of Gut, researchers set out to determine whether venous thromboembolism (TE) is more prevalent among inflammatory bowel disease (IBD) patients than control groups. TE is a condition in which a blood clot (thrombus) forms in a vein. This clot can limit blood flow through the vein, causing swelling and pain. Venous thrombosis can form anywhere in the venous system, which runs throughout the body, and can be life threatening.

The focus of the study was to determine if it is the inflammatory response or bowel-specific location that caused the TE relationship with IBD. To make this comparison, the researchers selected two other disease groups: rheumatoid arthritis because it is inflammatory related; and celiac disease because it is bowel related.

In the study, 618 patients with IBD, 243 with rheumatoid arthritis, 207 with celiac disease, and 707 control individuals were included. The control individuals were matched by age and sex to their respective disease group. All groups were individually asked to fill out a detailed questionnaire during a visit to the University of Vienna’s outpatient clinic. Only TE cases that could be confirmed by an approved radiological imaging process were included in the results. The researchers also gathered information on the IBD patients to determine if there was any relationship between TE and active disease or the presence of complications such as stenosis, fistula, or abscess.

After statistical analysis, the results showed that the prevalence of this clotting disease in the IBD group was significantly higher at 6.2% versus the 1.6% for its corresponding control group. This risk was significantly increased with age, particularly in those 45 years of age or older. Of the IBD patients, 60% had active disease present at the time of the TE. There was no significant difference between the prevalence of TE among Crohn’s disease, ulcerative colitis or indeterminate colitis subjects. Furthermore, TE in the celiac disease subjects was 1% compared to 1.9% for its corresponding control group and TE in rheumatoid arthritis subjects was 2.1% compared to 2.5% for its corresponding control group.

The findings establish that there is an increased risk of venous thromboembolism for IBD patients. Alternately, the results do not show increased risk of TE in those with celiac disease and rheumatoid arthritis. The features that cause an increased risk of TE in IBD patients must be disease specific not singularly inflammatory or bowel-specific. According to the researchers, “It is noteworthy that many thromboembolic events occurred during active disease or in the presence of complications such as stricture, fistulisation, or abscess.”

First published in the Inside Tract® newsletter issue 142 – March/April 2004
W Miehsler, W Reinisch, E Valic, et al. Is inflammatory bowel disease an independent and disease specific risk factor for thromboembolism? Gut. 2004;53(4):542-548