Low skeletal muscle density assessed by abdominal computerized tomography predicts outcome in children with chronic kidney disease.

Objective: Skeletal muscle loss and abnormal fat distribution are predictors of poor clinical outcomes in adults with chronic kidney disease (CKD). However, the relationship between body composition (muscle mass and adipose tissue) and prognosis in children with CKD has not been well elucidated.

Methods: The retrospective single-center study enrolled children with CKD and healthy group who underwent an abdominal Computerized tomography (CT) examination and compared the body composition of the third lumbar spine (L3) between the two groups. We defined the primary outcome as hemodialysis, peritoneal dialysis, kidney transplantation, or death. Logistic regression analysis was applied to assess the connection between low skeletal muscle density (SMD) and clinical and demographic variables. Multivariate Cox regression analysis was used to evaluate the risk factors for progression to the primary outcome. Kaplan-Meier survival analysis was performed to compare the effect of different body composition on event-free survival rate.

Results: 32 patients with CKD [eGFR: 14.89(8.86, 29.88) (mL/min/1.73m²)] and 66 heathy subjects [eGFR: 135.72(121.70, 161.29) (mL/min/1.73m²)] were recruited in our study. From the assessment of body composition assessed by CT, skeletal muscle area, SMD and skeletal muscle index (SMI) in CKD group was lower than those in healthy group (P<0.05). On the other hand, visceral fat area and visceral fat index in CKD group were significantly higher than those in healthy group (P<0.05). In logistic regression analysis, triglyceride (OR: 8.635, 95%CI: 1.153-64.687) was independently associated with low SMD. After adjusting clinical data and body composition, high serum albumin (HR: 0.873, 95%CI: 0.798-0.955) and high SMD (HR: 0.895, 95%CI: 0.822-0.974) were protective factors for delaying renal failure. Based on the Kaplan-Meier analysis, only the group with low SMD had lower event-free survival in comparison to the reference group (P<0.05).

Conclusions: These findings suggest that there is significant skeletal muscle loss and decrease in SMD in CKD children. Notably, low SMD is indicative of poor prognosis in CKD children.