Biomarkers, Abdominal Muscle, and Frailty in CKD

Chronic kidney disease (CKD) is a chronic condition associated not only with a decline in renal function but also with systemic effects such as inflammation, oxidative stress, muscle loss, and impaired physical function. It is hypothesized that the chronic inflammation and oxidative stress developing during the course of the disease contribute to alterations in skeletal muscle structure and function. However, data regarding the relationship of these processes with abdominal muscles in patients with advanced-stage CKD who are not undergoing dialysis are limited. This cross-sectional study aims to evaluate the associations between inflammatory and oxidative stress markers and abdominal muscle thickness and frailty in patients with stage 3-5 CKD not receiving dialysis. Serum monocyte chemoattractant protein-1 (MCP-1) is used as an inflammatory marker, while total antioxidant status (TAS), total oxidant status (TOS), and the oxidative stress index (OSI)-calculated from these values-are used to assess oxidative/antioxidative status. To assess abdominal muscles, the thicknesses of the rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles are measured via ultrasonography. Frailty is assessed using the FRAIL scale and the Clinical Frailty Scale. The study also aims to examine the clinical and functional characteristics across different stages of CKD by evaluating participants' physical performance, kinesiophobia, and kidney disease-specific quality of life. This study aims to simultaneously evaluate the associations of inflammation and oxidative stress markers with abdominal muscle thickness and frailty in the same patient group, and to conduct a more comprehensive examination of muscle and functional impairment in pre-dialysis patients with stage 3-5 CKD.