Hinton ZH, Fletcher AN, Ryan SP, et al. - Body mass index (BMI), American Society of Anesthesiologists (ASA) score, and Elixhauser Comorbidity Index are evaluated that are used to prognosticate perioperative outcomes, though little is known about their comparative predictive effects. Researchers examined the impacts of these indices on costs, operating room (OR) time, and length of stay (LOS) with the hypothesis that they would have a differential influence on each outcome variable. Between 2015 and 2018, a retrospective review of the institutional database was completed on primary TKA patients. They developed univariable and multivariable models to assess the strength of BMI, ASA, and Elixhauser comorbidities for predicting variations to total hospital and surgical costs, OR time, and LOS. The study enrolled a total of 1,313 individuals. The results of this study revealed that, although ASA, BMI, and Elixhauser comorbidities have the potential to impact result and cost, there are important variations in their predictive nature. Other measures like Elixhauser and ASA score were more indicative of cost outside of the OR and LOS, although BMI is independently predictive of intraoperative resource utilization. The findings indicate the differing impact of BMI, ASA, and patient comorbidities in impacting cost and time consumption throughout perioperative care.