E388: Association between Extended Venous Thromboembolism Prophylaxis and Venous Thromboembolism and Major Bleeding After Oncologic Colorectal Surgery

Multiple medical societies recommend extended VTE prophylaxis following abdominal and pelvic surgery for cancer. While adherence to extended VTE prophylaxis has been low, its effectiveness has not been evaluated using real-world data.

Methods: This study retrospectively analyzed a random 10% sample of the 2009-2022 IQVIA LifeLink PharMetrics Plus database, an administrative claims database representative of the commercially insured population of the United States. The study selected cancer patients undergoing formal colon or rectal resections. The primary outcomes were 90-day post-discharge VTE and bleeding events. The association of preoperative and intraoperative variables with the outcomes was assessed using univariate and multivariable main effects logistic regression models.

Results: Out of 13,931 patients, we excluded 143 (1.0%) for inpatient VTE, 510 patients (3.7%) for bleeding, and 252 patients (1.8%) for a prolonged hospital stay during their index hospitalization. The remaining 13,117 eligible operations were comprised of 35.0% laparoscopic colon surgeries, 33.4% open colon surgeries, 17.3% laparoscopic rectal surgeries, and 14.2% open rectal surgeries. The median age was 59 years and 51.9% were female. Extended VTE prophylaxis prescriptions were filled for 676 patients (5.2% of the study population), primarily with enoxaparin (95.5%), and increased over time (1.7% in 2010 to 12.0% in 2021). After risk adjustment, extended VTE prophylaxis was not associated with post-discharge VTE (OR 1.011; 95% Confidence Intervals 0.996-1.026) or bleeding [OR 0.995 (0.978-1.013)]. The only factor significantly associated with VTE was the Elixhauser score [OR 1.011 (1.010-1.013)]. Age (10-year increment) [OR 0.993 (0.989-0.996)] and Elixhauser score [OR 1.012 (1.010-0.014)] were associated with bleeding events.

Conclusions: The majority of cancer patients undergoing formal colon and rectal resections did not receive extended VTE prophylaxis. This did not appear to affect their risk of postoperative VTE or bleeding in our sample. Further research should focus on the groups of patients most likely to benefit from such interventions.