Computed tomography-based body composition is associated with adverse clinical outcomes among older patients with sepsis in the emergency department

Abstract

Purpose: To investigate the association between body composition and adverse clinical outcomes in older patients with sepsis in the emergency department.

Methods: Body composition, including the skeletal muscle area, skeletal muscle index (SMI), mean skeletal muscle density (SMD), and intramuscular fat area, was measured at the level of the third lumbar vertebra (L3) on abdominal computed tomography scans. Clinical outcomes included 90-day mortality, 90-day readmission, and discharge to long-term care. According to sex-specific cut-off values of L3 SMI and SMD, patients were divided into low SMI, low SMD, both low SMI and low SMD, and neither low SMI nor low SMD groups.

Results: In total, 443 patients were included, 162 (36.6%) of whom died. Lower SMI and SMD, as continuous variables, were independent risk factors for 90-day mortality (adjusted hazard ratio [HR] = 0.947 and 0.963, respectively, both p < 0.001). Cut-off values of L3 SMI and L3 SMD were 32.24 cm²/m² and 30.01 HU for men and 28.28 cm²/m² and 28.20 HU for women, respectively. The both low SMI and low SMD group had an increased risk of 90-day mortality (adjusted HR=3.059, p < 0.001), 90-day readmission (adjusted odds ratio [OR]=2.859, p = 0.006), and discharge to long-term care (adjusted OR = 2.814, p = 0.007).

Conclusions: Lower muscle mass and muscle quality, as measured by skeletal muscle index and density, were independent risk factors for mortality among older patients with sepsis in the emergency department. Furthermore, patients with both low muscle mass and quality had an increased risk of mortality, readmission, and discharge to long-term care.

Keywords: Body composition; Computed tomography; Older adults; Sarcopenia; Sepsis.