Risk assessment of venous thromboembolism in inflammatory bowel disease by inherited risk in a population-based incident cohort

BACKGROUNDInflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic inflammatory disease of the digestive tract with increasing prevalence globally. Although venous thromboembolism (VTE) is a major complication in IBD patients, it is often underappreciated with limited tools for risk stratification. AIMTo estimate the proportion of VTE among IBD patients and assess genetic risk factors (monogenic and polygenic) for VTE. METHODSIncident VTE was followed for 8465 IBD patients in the UK Biobank (UKB). The associations of VTE with F5 factor V leiden (FVL) mutation, F2 G20210A prothrombin gene mutation (PGM), and polygenic score (PGS003332) were tested using Cox hazards regression analysis, adjusting for age at IBD diagnosis, gender, and genetic background (top 10 principal components). The performance of genetic risk factors for discriminating VTE diagnosis was estimated using the area under the receiver operating characteristic curve (AUC). RESULTSThe overall proportion of incident VTE was 4.70% in IBD patients and was similar for CD (4.46%), UC (4.49%), and unclassified (6.42%), and comparable to that of cancer patients (4.66%) who are well-known at increased risk for VTE. Mutation carriers of F5/F2 had a significantly increased risk for VTE compared to non-mutation carriers, hazard ratio (HR) was 1.94, 95% confidence interval (CI): 1.42-2.65. In contrast, patients with the top PGS decile had a considerably higher risk for VTE compared to those with intermediate scores (middle 8 deciles), HR was 2.06 (95%CI: 1.57-2.71). The AUC for differentiating VTE diagnosis was 0.64 (95%CI: 0.61-0.67), 0.68 (95%CI: 0.66-0.71), and 0.69 (95%CI: 0.66-0.71), respectively, for F5/F2 mutation carriers, PGS, and combined. CONCLUSIONSimilar to cancer patients, VTE complications are common in IBD patients. PGS provides more informative risk information than F5/F2 mutations (FVL and PGM) for personalized thromboprophylaxis.