Introduction to entropy balancing: A case study on the association between statin therapy and outcomes after traumatic injury.

Abstract

Single-institution data identified statin therapy's association with lower rates of venous thromboembolism following traumatic injury. This association has not been evaluated in a larger cohort of patients. The aim of this study was to evaluate the association between preinjury statin therapy and clinical outcomes among trauma patients. This is a cohort study evaluating trauma patients in a statewide collaborative quality initiative. We included adults (≥18 years old) with an Injury Severity Score ≥5 admitted to the hospital between January 1, 2013, and June 30, 2024. We excluded patients with no signs of life or who died in the emergency department. The exposure was preinjury statin usage. The primary outcome was in-hospital mortality, and secondary outcomes included venous thromboembolism, myocardial infarction, stroke, cardiac arrest, and sepsis. We evaluated risk-adjusted rates using entropy balancing, a technique that reweights control covariates to ensure balance between the exposure and control populations to allow for robust comparison of treatment effects. We also performed a sensitivity analysis using propensity score matching. We evaluated 293,852 patients across 35 trauma centers (208,841 without and 85,211 with statin exposure). After entropy balancing of controls, patients were demographically similar between these 2 cohorts from the standpoints of age, gender, race/ethnicity, injury mechanism and severity, and comorbidities. Risk-adjusted outcomes of interest were statistically similar between the statin and control cohorts for mortality, venous thromboembolism, myocardial infarction, stroke, and cardiac arrest. Additionally, similar findings were also observed in the sensitivity analysis using propensity score matching. Using multi-institutional data, we found no association between preinjury statin therapy exposure and the outcomes of mortality, venous thromboembolism, myocardial infarction, stroke, or cardiac arrest. Although statin therapy is an important medication in the treatment of cardiovascular disease it may not offer a protective effect that influences acute outcomes in the setting of traumatic injury.