Background

Venous Thromboembolic Event (VTE) is the leading cause of mortality following Metabolic and Bariatric Surgery (MBS). The objective of this study is to identify patients who are at high risk for VTE and who may benefit from extended chemoprophylaxis.

Methods

Using the 2015-2019 MBSAQIP participant user file (PUF) we identified 696,069 patients. Using logistic regression analysis, we identified pre- and post-operative risk factors associated with VTE and validated our model externally using the MBSAQIP 2020-2021 datasets. The Hosmer-Lemeshow test was used for goodness of fit and calibration. We also compared our model discriminatory capability to other VTE risk assessment tools.

Results

The overall incidence of VTE after MBS was 0.40% (2,759 patients). Within the training phase, the model presented a good calibration (Hosmer-Lemeshow goodness of fit , X2 = 11.06, p-value = 0.198 and discrimination (c-statistic = 0.66). External validation showed a similar performance with a c-statistic = 0.64; 95% CI 0.62-0.66. A cut point of 0.4% resulted in a sensitivity of 48.28% with 24% of patients having a VTE risk greater than 0.4%. Our risk model includes age, gender, race, BMI, operation length, procedure type, preop functional status, preop vein thrombosis, previous obesity/foregut surgery, revision or conversion status, postop surgical site infection, transfusion and unplanned readmission or reoperation.

Conclusions

VTE following MBS can result in increased mortality rates. Our model suggests that patients with VTE risk of 0.4% or more in the first 30 days following surgery may benefit from extended chemoprophylaxis.