Background: Venous thromboembolism (VTE) presents a common and life-threatening extra-intestinal complication of inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC).
The aim of this study is to investigate the prevalence of thromboembolism in patients in a Finnish IBD cohort, and to analyze VTE risk factors.
Methods: A register of IBD patients was established in 1986 at Tampere University Hospital, Tampere, Finland, and it was maintained until the end of 2007. A total of 1915 patients (47% female) were included, of which 65.4% were diagnosed with UC and 28.8% with CD. The register included all IBD patients in the area regardless of the level of difficulty of the disease.
Index patients were identified from the IBD register on the diagnosis of either thrombophlebitis, deep venous thromboembolism, and/or pulmonary embolism.
VTEs that occurred 1986–2014 were collected retrospectively. A control group of non-VTE IBD patients was collected from the IBD register as well. Two controls for each case were matched regarding gender, year of birth, IBD diagnosis, and location of the disease
Results: Between 1986 and 2014, 85 IBD patients out of 1915 developed one or several venous thromboembolisms (range 1–5 VTE events). VTE index patients (49.4% female) included 57 UC (67%), 27 (32%) CD, and 1 (1%) IBD unclassified. The incidence was 2.20/1000 patient years. 39% of the first VTE events were deep venous thromboembolism (DVT) in lower extremity and 31% were pulmonary embolism (PE). VTE group and non-VTE group are compared in Table 1.
43.8% of gut-operated and 18.2% of non-gut-operated VTE patients had more than one VTE event (p=0.086). In a sub-group of 1986–2007 data, the extent of the UC disease correlated with the number of VTE events (rS=0.471, p=0.005).
Conclusions: According to our study and in agreement of previous work, IBD patients have roughly a twofold risk of VTE to that of general population. In a sub-group, the extent of CU correlated with the number of VTE events.
 Grainge M et al. (2010), Venous thromboembolism during active disease and remission in inflammatory bowel disease: a cohort study, Lancet 2010; 375:657–63
 Kappelman M et al. (2011), Thromboembolic risk among Danish children and adults with inflammatory bowel diseases a population-based nationwide study, Gut 2011;60:937–943