The Associations of Psoas and Masseter Muscles With Sarcopenia and Related Adverse Outcomes in Older Trauma Patients- A Retrospective Study

Abstract Background: There is an emerging role for the radiological evaluation of the psoas muscle as a marker of sarcopenia, and as a prognostic discriminant in elderly patients with traumatic injuries. Older trauma patients are more likely to undergo cranial than abdomino-pelvic imaging. Identifying sarcopenia using masseter cross sectional area (M-CSA) has shown correlation with mortality. We sought to determine the correlation between psoas: lumbar vertebral index (PLVI) and the M-CSA, and their association with health outcomes. Methods: Patients aged 65 or above, who presented as a trauma call over a 1 year period were included if they underwent cranial or abdominal CT imaging. Images were retrospectively analyzed to obtain PLVI and mean M-CSA measurements. Electronic records were abstracted for demographics and outcomes. Logistic regression methods, log scale analyses, Cox regression model and Kaplan-Meier plots were used to determine association of sarcopenia with outcomes. Results: There were 155 eligible patients in the M-CSA group and 204 patients in the PLVI group. Sarcopenia was defined as the lowest quartile in each group. Both PLVI and M-CSA measurements were available in 142 patients. Pearson’s correlation indicated a weakly positive linear relationship (r=0.35, p<0.001) between these. There was no statistical association between M-CSA sarcopenia status and any measured outcomes. Those with PLVI sarcopenia were more likely to die in hospital (adjusted OR 3.38, 95% CI 1.47-9.73, p=0.006) and at 2-years (adjusted HR 1.90, 95% CI 1.11-3.25, p=0.02). Only 29% patients with PLVI sarcopenia were discharged home, compared with 58% without sarcopenia (p=0.001).Conclusion: Sarcopenia, defined by PLVI, is predictive of increased in-patient and 2- year mortality. Our study did not support prognostic relevance of M-CSA. Further research should be directed at improving the validity of masseter measurements or identifying alternative radiological determinants of sarcopenia on cranial imaging.