CT anthropometric analysis of the prognosis of traumatic brain injury: A retrospective study to compare between psoas muscle and abdominal skeletal muscle.

BACKGROUND: Recent studies have suggested that skeletal muscle area (SMA) and psoas muscle area (PMA), markers for sarcopenia, are associated with the prognosis of many diseases. However, it remains unclear which of the two is a superior prognostic marker. Thus, the objective of this study was to analyse these markers in patients with traumatic brain injury (TBI). METHODS: Patients with TBI [abbreviated injury scale (AIS) score of 4 or 5] were selected. Those with an AIS score of 4 or 5 for chest, abdomen, or extremity lesion were excluded. Clinical data, including Glasgow Outcome Scale (GOS), mortality, and anthropometric data, were collected. SMA and PMA were measured. Skeletal muscle index (SMI) and psoas muscle index (PMI) were calculated for each muscle area divided by height squared. The good prognosis group was defined as patients with a GOS score of 4 to 5. The poor prognosis group was defined as those with a GOS score of 1-3. Data of both groups were analysed for the overall prognosis. After excluding patients with a hospital stay of 1 or 2 days, the modified prognosis and mortality of patients were analysed. RESULTS: A total of 212 patients were enrolled in the statistical analysis. Patients with good prognosis showed a larger PMA (17.4 cm2 vs. 15.0 cm2, P = 0.002) and PMI (6.1 cm2/ m2 vs. 5.3 cm2/ m2, P = 0.001). After modification, patients with good prognosis showed a larger PMA (17.4 cm2 vs. 14.9 cm2, P = 0.002) and PMI (6.1 cm2/ m2 vs. 5.3 cm2/ m2, P = 0.01). On binary logistic regression analysis, PMI was found to be a significant risk factor for the modified prognosis (Odds ratio (OR) (95% confidence interval (CI)): 0.763 (0.633 - 0.921), P = 0.005) and modified mortality (OR (95% CI): 0.740 (0.573 - 0.957), P = 0.022). CONCLUSION: Less amount of psoas muscle (PM) was found to be a significant risk factor for the prognosis of patients with TBI. PM was a better prognostic marker than skeletal muscle (SM) in patients with TBI. Further studies are needed to increase our understanding of sarcopenia and TBI.