Hospital resource index, race/ethnicity, and postoperative venous thromboembolism risk: A causal mediation analysis

Background: We examined whether hospital resources mediated the association between race/ethnicity and postoperative VTE, in a national cohort. Methods: National Inpatient Sample data were restricted to major abdominal surgeries (1993–2020) performed for malignancies. Hospital resource index was as a summary measure of hospital size, teaching status, and private payor proportions. The composite VTE outcome included postoperative deep vein thrombosis and pulmonary embolism. Adjusted logistic regression with 4-way decomposition described joint and mediating effects. Results: Among 1,169,862 surgeries, unadjusted VTE rate was 1.0 ​% (14,789). VTE risk was 28 ​% higher for Black/African Americans (adjusted Odds Ratio ​= ​1.28, 95 ​% CI: 1.21, 1.37) relative to White/Caucasians. VTE risk was lower among Black individuals as hospital resource index increased (excess risk ​= ​−0.005, p ​< ​0.001), with an effect size of likely minimal clinical impact. Conclusion: Cohorts that are more vulnerable to postoperative VTE did not meaningfully benefit from improving hospital resources. It is likely that lifestyle modifying behaviors, environmental factors, and comorbidity management are more influential in reducing risks.