Multicenter Analysis of Standard of Care versus Oxandrolone versus Testosterone in burn hypermetaboliSm (MASCOTS)

Severe burn injury results in a profound hypermetabolic state that complicates management and recovery. Oxandrolone has historically been used to help attenuate this response, but its withdrawal from the United States (US) market has led to increased use of alternative anabolic agents such as testosterone and human growth hormone. However, studies comparing the efficacy and safety between these alternative anabolic agents in adult burn patients remain limited. In this multicenter study, patients were stratified based on if they received testosterone, oxandrolone, human growth hormone, or no anabolic supplementation. Baseline characteristics and clinical outcomes were analyzed with ANOVA and Chi-square testing as appropriate. Propensity score matching was used to adjust for baseline differences in injury severity and patient characteristics. 813 patients who sustained major burn injuries between June 2022 and June 2025 across 12 verified US burn centers were analyzed. Anabolic supplementation was not associated with improved inpatient weight maintenance when compared with no anabolic supplementation (p=0.064), nor with differences in median weight change. Patients receiving anabolic therapy experienced longer hospital and intensive care unit stays (p=0.026). Overall mortality did not differ between treated and untreated patients (p = 0.885); however, mortality was higher among patients treated with oxandrolone compared with testosterone (p=0.001). Anabolic therapy was associated with higher rates of venous thromboembolic events (p = 0.019). These findings underscore that optimizing anabolic therapy will require balancing efficacy, safety, and economic considerations, with a focus on long-term functional outcomes beyond initial hospital stay.