Serum
myostatin and
indoxyl sulfate (IS) levels increase with kidney function decline and may function as
uremic toxins in
chronic kidney disease (CKD)-related
sarcopenia. Herein, we analyzed the association between serum
myostatin and IS levels and
sarcopenia in patients with CKD, by performing a post hoc analysis of baseline data extracted from the RECOVERY study (clinicaltrials.gov: NCT03788252) of 150 patients with CKD. We stratified patients into two groups according to the median value of
myostatin (cutoff 4.5 ng/mL) and IS levels (cutoff 0.365 mg/dL). The proportion of patients with
sarcopenia was higher in those with high IS levels but lower in those with high
myostatin levels. The skeletal muscle mass index (SMI) and handgrip strength (HGS) were significantly lower in patients with high IS levels but significantly higher in patients with high
myostatin levels. IS levels showed a negative correlation with glomerular filtration rate (GFR), SMI, and HGS. However,
myostatin levels were positively correlated with SMI and HGS, but not with GFR.
Sarcopenia was independently associated with age and IS level after adjustment. Increased levels of serum total IS might play a role in
sarcopenia, while increased levels of serum
myostatin are associated with muscle mass in patients with CKD.