Inflammatory bowel disease is a risk factor for recurrent venous thromboembolism.

BACKGROUND & AIMS: Patients with inflammatory bowel disease (IBD) are at increased risk of a first venous thromboembolism (VTE), yet their risk of recurrent VTE is unknown. We performed a cohort study to determine the risk for recurrent VTE among patients with IBD compared with subjects without IBD.

METHODS: We assessed 2811 patients with IBD for a history of VTE, recruited from outpatient clinics at 14 referral centers (June 2006-December 2008). Patients with VTE before a diagnosis of IBD or those not confirmed to have VTE, cancer, or a VTE other than deep vein thrombosis or pulmonary embolism, were excluded. Recurrence rates were compared with 1255 prospectively followed patients without IBD that had a first unprovoked VTE (not triggered by trauma, surgery, or pregnancy). The primary end point was symptomatic, objectively confirmed, recurrent VTE after discontinuation of anticoagulation therapy after a first VTE.

RESULTS: Overall, of 116 IBD patients who had a history of first VTE, 86 were unprovoked. The probability of recurrence 5 years after discontinuation of anticoagulation therapy was higher among patients with IBD than patients without IBD (33.4%; 95% confidence interval [CI]: 21.8-45.0 vs 21.7%; 95% CI: 18.8-24.6; P = .01). After adjustment for potential confounders, IBD was an independent risk factor of recurrence (hazard ratio = 2.5; 95% CI: 1.4-4.2; P = .001).

CONCLUSIONS: Patients with IBD are at an increased risk of recurrent VTE compared to patients without IBD.