To Örebro University

Introduction: Deep vein thrombosis (DVT) and pulmonary embolism (PE) are recognized complications following bariatric surgery, with incidences reported between 0.3% and 2.2%. While thromboprophylaxis is recommended, the optimal duration, dosage, and timing remain debated. This study evaluates the association between thromboprophylaxis regimens and postoperative DVT/PE and bleeding complications in a nationwide cohort.

Method: A retrospective cohort study was conducted using data from the Scandinavian Obesity Surgery Registry (SOReg) from 2010 to 2023. Data included demographics, surgical details, thromboprophylaxis regimens, and six-week follow-up on DVT/PE and bleeding. Thromboprophylaxis duration (<7, 7–10, 11–14, >14 days) and initiation (preoperative vs. postoperative) were analysed using univariable and multivariable logistic regression, adjusting for risk factors.

Result: Among 83,801 patients, 48,344 had thromboprophylaxis data, and 30,800 had recorded initiation timing. The overall incidence of DVT/PE was 0.09%, with no significant differences across treatment durations or initiation timing (p=0.33 and 0.12). Prior DVT/PE (OR 4.10, 95% CI 1.40–12.03, p=0.010) and intraoperative bleeding (OR 6.39, 95% CI 1.46–27.98, p=0.014) were associated with higher DVT/PE risk. Postoperative thromboprophylaxis initiation was linked to lower intraoperative bleeding risk (OR 0.66, 95% CI 0.47–0.93, p=0.046), while male sex, older age, cardiovascular disease, and antidepressant use were associated with increased postoperative bleeding risk.

Discussion: Thromboprophylaxis duration and timing did not significantly affect DVT/PE incidence. However, postoperative initiation was associated with a lower risk of intraoperative bleeding. These findings may guide thromboprophylaxis strategies in bariatric surgery patients.