Surgery and the Subtype of Inflammatory Bowel Disease Impact the Risk of Venous Thromboembolism After Hospital Discharge.

BACKGROUND: Surgery for inflammatory bowel disease (IBD) is associated with an increased risk of venous thromboembolism (VTE) during hospitalization. It is unclear whether this association persists after hospital discharge. AIMS: We assessed the association between surgery and VTE following hospital discharge in IBD. METHODS: We conducted a population-based cohort study between 2002 and 2016 in Ontario, Canada. Adults with IBD hospitalized for ≥ 72 h who underwent an intra-abdominal surgery were compared to hospitalized, nonsurgical IBD patients. Multivariable Cox proportional hazard models were used to compare VTE risk within 12 months of discharge. RESULTS: A total of 80,445 hospital discharges were analyzed: 60% Crohn's disease (CD) and 40% ulcerative colitis (UC). The median time to VTE was three times longer for nonsurgical patients with CD and 1.6 times longer for nonsurgical patients with UC. Compared with nonsurgical patients, surgery for CD was associated with a lower cumulative risk of VTE in the 2 weeks after discharge and persisted through to 12 months after discharge (adjusted HR 0.24; 95% CI 0.15-0.40). In contrast, urgent surgery for UC was associated with an increased risk of VTE. The increased risk was greatest at 2 weeks after discharge (aHR, 1.80; 95% CI 1.26-2.57) and declined progressively over the course of 12 months. CONCLUSIONS: Surgery was associated with a greater risk of VTE after hospital discharge in UC but not CD. In patients with UC who have undergone urgent surgery, healthcare providers should consider an extended period of prophylaxis after hospital discharge.