Measurement of psoas muscle size using existing computed tomography to predict patient outcomes in emergency departments

Abstract

Sarcopenia is a major physical factor of frailty and can be predicted by existing patient computed tomography (CT) scans. The objective of this study was to investigate the relationships between prognosis of elderly patients visiting the emergency department and psoas muscle size measurements from CT scans that were acquired in other purpose. This was a retrospective study in a single center. The psoas muscle size (cross-section) and attenuation at the L3 vertebra were measured on CT scans. Logistic regression analysis was used to determine the association between mortality and muscle size and muscle attenuation after adjustment of basic characteristics. Also, we constructed receiver operating characteristic curves. A total of 279 patients were enrolled with diagnoses categorized from 13 chapters from on International Classification of Diseases 10th Revision (ICD-10). There were 56 patients (20.1%) admitted to the ICU, and 51 patients (18.3%) died in the hospital during the clinical process. The area under the receiver operating characteristic (AUROC) of muscle size for prediction of ICU admission was 0.706 (0.649-0.759), and the cut-off value was 390.18 with 51.8% sensitivity and 87.9% specificity. The AUROC of muscle size for prediction of death was 0.904 (0.864-0.936), and the cut-off value was 587.41 with 92.2% sensitivity and 78.5% specificity. Using existing CT can be an appropriate method for an early diagnosis of sarcopenia in older patients. In this study, measurement of muscle size using CT was shown to be a feasible modality for predicting poor prognoses for older patients.