Clinical utility of computed tomography-based evaluation of trunk muscles in primary sclerosing cholangitis

Sarcopenia is well recognized as a prognostic factor of chronic liver diseases. However, its impact on the clinical course of primary sclerosing cholangitis (PSC) is unclear. This study aimed to clarify the importance of trunk muscles evaluated by computed tomography (CT) in the pathophysiology of patients with PSC.

22 PSC patients (12 men, mean age 42.8 years) were enrolled in this study. Patients who died of hepatic failure or had to receive liver transplantation were defined as event group. 44 age- and gender-matched individuals without hepatic disorder were served as controls. At the level of third lumbar vertebrae, the area of psoas muscle and trunk muscle as well as the CT values of multifidus muscle and subcutaneous fat were evaluated. Based on these, skeletal muscle index (SMI), psoas muscle mass index (PMI) and intramuscular adipose tissue content (IMAC) were calculated. Then we analyzed the relationship between these parameters and laboratory data, Fibrosis-4 index, MELD score and Mayo risk score.

At baseline evaluation, SMI and PMI were statistically lower in male PSC patients compared with those in controls (P < 0.05). In male PSC, regarding the laboratory data, PMI was associated with total bilirubin, ALT, ALP, and platelet count (P < 0.05). We found close relationship between PMI and MELD score (R² = 0.42, P = 0.02). PMI also decreased statistically in male Event group than in non-event group (4.85 vs 7.20, P = 0.01).

Skeletal muscle mass evaluated by CT scan can be suitable for evaluating clinical and prognostic marker in male PSC.