Use of post-discharge heparin prophylaxis and the risk of venous thromboembolism and bleeding following bariatric surgery.

INTRODUCTION Venous thromboembolism (VTE) is a significant cause of morbidity and mortality after bariatric surgery. Roughly 80% of VTEs occur post-discharge. The frequency of post-discharge heparin (PDH) prophylaxis use is unknown, and evidence about benefits and risks is limited. We aimed to determine the rate of use of PDH prophylaxis and evaluate its relationship with VTE and bleeding events. METHODS Using the Truven Health MarketScan® database, we performed a retrospective cohort study (2007-2015) of adult patients who underwent sleeve gastrectomy or gastric bypass. We determined PDH prophylaxis from outpatient pharmacy claims, and post-discharge 90-day VTE and bleeding events from outpatient and inpatient claims. We used propensity score-adjusted regression models to mitigate confounding bias. RESULTS Among 43,493 patients (median age 45 years; 78% women; 77% laparoscopic gastric bypass, 17% laparoscopic sleeve gastrectomy, 6% open gastric bypass), 6% received PDH prophylaxis. Overall, 224 patients (0.52%) experienced VTEs, and 806 patients (1.85%) experienced bleeding. The unadjusted VTE rate did not differ between patients who did and did not receive PDH prophylaxis (0.39% vs. 0.52%, respectively; p = 0.347). The unadjusted bleeding rate was higher for the PDH prophylaxis group (2.74% vs. 1.80%, p < 0.001). In our adjusted analysis, a 23% lower risk of VTE in the PDH prophylaxis group was not statistically significant (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.41 to 1.46), whereas the 47% higher risk of bleeding was statistically significant (OR 1.47, 95% CI 1.14 to 1.88). CONCLUSIONS PDH prophylaxis after bariatric surgery is uncommon. In our analysis, use was not associated with a lower VTE risk but was associated with a higher bleeding risk.