A clinical predictive model for post-hospitalisation venous thromboembolism in patients with inflammatory bowel disease

Background Patients with inflammatory bowel disease (IBD) are at increased risk of venous thromboembolism (VTE) during hospitalisation and potentially post-discharge. Aims To determine the incidence and risk factors for post-discharge VTE in IBD patients and create a point of care predictive model to assess VTE risk. Methods Hospitalised IBD patients were identified from our institutional discharge database between 2009 and 2016, and were assessed for VTE by chart review. Risk factors for VTE within 3 months of discharge were determined by univariable and multivariable logistic regression. A point of care model was created using variables from the univariate analysis with P < 0.05, and internally validated by bootstrap methods. Results Sixty-six of 2161 eligible discharges (3%) were associated with VTE within 6 months of hospitalisation. The median time to event was 37 days (range 3-182 days). On multivariable analysis age >45 years (OR 3.76; 95% CI 1.80-7.89) and multiple admissions (OR 2.62; 95% CI 1.34-5.11) were independently associated with VTE risk. Our final model incorporated age >45 years, multiple admissions, intensive care unit admission, length of admission >7 days and central catheter and was able to discriminate between discharges associated with and without VTE (optimism-corrected c-statistic, 0.70; 95% CI 0.58-0.77). By limiting treatment to a high-risk group, extended thromboprophylaxis could be avoided in 92% of discharges with a miss rate of 1.6% (32/1982 discharges). Conclusion Patients with IBD remain at risk of VTE after hospital discharge. Our model may help clinicians stratify which patients will benefit most from extended thrombophrophylaxis.