Thromboembolism is associated with poor prognosis and high mortality in patients with inflammatory bowel disease: A case-control study.

Background: The information on the risk of thromboembolism (TE) in inflammatory bowel disease (IBD) and its predictors are lacking, especially from developing countries. The present study evaluated the prevalence, predictors, and prognosis of TE in IBD.

Methods: This case-control study included 35 patients with IBD (ulcerative colitis [UC, n = 25]; Crohn's disease [CD], n = 10) and history of TE, from a cohort of 3597 patients (UC n = 2752, CD n = 845) under follow-up from 2005 to 2018. Details on demographics, extraintestinal manifestations (EIMs), patient status, type and outcomes of TE, treatment details, and disease course were compared with IBD patients without TE (age, gender, and duration of follow-up matched) in the ratio of 1:4.

Results: Prevalence of TE in IBD was 0.9% (UC-0.89%, CD-1.2%). Among TE patients (mean age: 34.9 ± 13.1 years, 48.6% males), median duration from diagnosis to TE was 12 (inter-quartile range [IQR]: 3-36) months, 37% had other EIMs, 94.1% had moderate/severe disease at time of TE, 62.8% had steroid-dependent/refractory disease, and 5 patients (14.2%) died because of disease-related complications. Lower limb was the commonest site (57.1%), 14.3% had pulmonary TE, and 31.4% had involvement of multiple sites. Phenotypically, more patients with TE (among UC) had steroid-dependent disease (60% vs. 25%, p = 0.001), pancolitis (76% vs. 36%, p = 0.002), chronic continuous disease course (44% vs. 19%, p = 0.009), and acute severe colitis (48% vs. 18%, p = 0.002), of which the latter three were also independent predictors of TE.

Conclusion: Approximately 1% of patients with IBD develop thromboembolism relatively early during their disease course, and TE is associated with severe disease and higher disease-related complications including mortality.