Extended Venous Thromboembolism Prophylaxis After Elective Surgery for IBD Patients: Nomogram-Based Risk Assessment and Prediction from Nationwide Cohort

Abstract

Identification of risk factors for postoperative venous thromboembolism is an important step to reduce the morbidity associated with this potentially preventable complication after elective surgery for patients with IBD. This study aimed to determine the risk factors for 30-day venous thromboembolism after abdominal surgery for patients with venous thromboembolism, identify potential indications for extended thromboprophylaxis, and develop a nomogram for prediction of risk. This is a retrospective cohort study from a prospectively collected database. The American College of Surgeons National Surgical Quality Improvement Program Participant User File from 2005 to 2016 was used for data analysis. All patients with IBD undergoing elective abdominopelvic bowel surgery were included. The primary outcomes were the incidence of in-hospital and postdischarge venous thromboembolism within 30 days of the index abdominopelvic surgery. A total of 24,182 patients met the inclusion criteria. Thirty-day total and postdischarge rates of venous thromboembolism were 2.5% (n = 614) and 1% (n =252). Forty-one percent (252/614) of venous thromboembolism events occurred after hospital discharge. Univariate analysis assessed 37 variables for association with study outcomes. On multivariate logistic regression analysis, older age, steroid use, bleeding disorders, open surgery, hypertension, longer operative time, and preoperative hospitalization were associated with venous thromboembolism before discharge and also postoperative transfusion, steroid use, pelvic and enterocutaneous fistula surgery, and longer operative time were associated with venous thromboembolism after discharge. A nomogram was constructed for each outcome, translating multivariate model parameter estimates into a visual scoring system where the estimated probability of venous thromboembolism can be calculated. This study was limited by its retrospective nature and the limitations inherent to a database. Given the higher risk of venous thromboembolism in patients with IBD after elective abdominopelvic surgery compared with other indications, an accurate prediction of venous thromboembolism before and after discharge using the proposed nomogram can facilitate decision making for individualized extended thromboprophylaxis in the preoperative setting as a screening tool. See Video Abstract at http://links.lww.com/DCR/A711.