The triglyceride-glucose (TyG) index and triglyceride-glucose-body mass index (TyG-BMI) are emerging surrogate markers of insulin resistance and metabolic risk. However, their comparative prognostic value in critically ill older adults with atherosclerotic cardiovascular disease (ASCVD) remains unclear. We aimed to compare the prognostic performance of the TyG index and TyG-BMI for 90-day all-cause mortality in this high-risk population.