Incidence and risk factors for venous thrombosis among patients with inflammatory bowel disease in China: a multicenter retrospective study

BACKGROUND/AIMS: Risk of venous thrombosis is increased in patients with inflammatory bowel disease (IBD); data on Asian IBD patients is limited and status quo of thrombosis screening and prophylaxis are unknown. Therefore, we aimed to investigate the incidence, screening, prophylaxis, and risk factors for venous thrombosis among Asian IBD patients. METHODS: Medical files of patients with Crohn’s disease (CD) and ulcerative colitis (UC) from 17 hospitals across China between 2011 and 2016 were reviewed for venous thrombosis, use of screening and prophylaxis. A case-control study was performed among hospitalized patients with venous thrombosis and their age-, sex-matched IBD controls hospitalized around the same period; disease characteristics and known provoking factors of venous thrombosis were recorded. Risk factors were analyzed in both univariate and logistic regression analyses. RESULTS: A total of 8,459 IBD patients were followed for 12,373 person-year. Forty-six patients (0.54%) had venous thrombosis, yielding an incidence of 37.18 per 10,000 person-year. Incidence increased with age, especially among CD. Less than 20% of patients received screening tests and 35 patients (0.41%) received prophylaxis. Severe disease flare was an independent risk factor for venous thrombosis (odds ratio [95% confidence interval]: CD, 9.342 [1.813– 48.137]; UC, 5.198 [1.268–21.305]); past use of steroids and extensive involvement were 2 additional risk factors in CD and UC, respectively. CONCLUSIONS: Incidence of venous thrombosis in China was 37.18 per 10,000 person-year (0.54%). Use of screening and prophylaxis were rare. Severe disease flare was an independent risk factor for thrombosis among hospitalized patients.