Abstract: Objective  To explore the correlation between serum sclerostin(SOST) and CKD-mineral and bone disorder(CKD-MBD) in patients with chronic kidney disease(CKD). 
Methods  A total of 120 patients with CKD stage 3-5 were selected and divided into CKD stage 3 group(n=40), CKD stage 4 group(n=40) and CKD stage 5 group(n=40) according to different stages of CKD. In addition, 40 age-and gender-matched healthy subjects who underwent physical examination were selected as the control group. The estimated glomerular filtration rate(eGFR), serum creatinine(SCr), blood urea nitrogen(BUN), hemoglobin(Hb) levels were compared in each group. The blood calcium(Ca), blood phosphorus(P), calcium phosphorus product(Ca·P), alkaline phosphatase(AKP), albumin(ALB) levels, and bone mineral density(BMD) were compared. The SOST, levels of intact parathyroid hormone(iPTH), 25-hydroxy vitamin D3［25-（OH）D3］ were observed, and the correlation between SOST and laboratory indexes was analyzed. 
Results  Compared with the control group, eGFR, Hb, and 25-（OH）D3 were significantly decreased, while SCr, BUN, SOST, and iPTH were significantly increased in CKD stage 3-5 groups(P＜0.05). Compared with CKD stage 3 group, eGFR, Hb, and 25-（OH）D3 were significantly decreased and SCr, BUN, SOST, and iPTH were significantly increased in CKD stage 4 and 5 groups(P＜0.05). Compared with CKD stage 4 group, eGFR, Hb, and 25-（OH）D3 were significantly decreased and SCr, BUN, SOST, and iPTH were significantly increased in CKD stage 5 group(P＜0.05). Compared with the control group, Ca, ALB and BMD in CKD stage 3 group were significantly decreased(P＜0.05). Ca, ALB and BMD in CKD stage 4 group were significantly decreased, and P, and Ca·P were significantly increased, as compared with the control group(P＜0.05). Ca, ALB and BMD in CKD stage 5 group were significantly lower and P, Ca·P, and AKP were significantly higher than those in the control group(P＜0.05). Compared with CKD stage 3 group, Ca and BMD in CKD stage 4 group was significantly decreased, while P, Ca·P, and AKP were significantly increased(P＜0.05). Ca and BMD were significantly lower and P and Ca·P were significantly higher in CKD stage 5 group than in CKD stage 3 group(P＜0.05). Ca and BMD decreased significantly and P, Ca·P, and AKP increased significantly in CKD stage 5 group, as compared with CKD stage 4 group(P＜0.05). SOST in patients with CKD stage 3-5 groups was negatively correlated with eGFR, Hb, Ca, 25-（OH）D3 and BMD(r=- 0.910, -0.660, -0.426, -0.393, -0.223, P＜0.05), and positively correlated with SCr, P, Ca·P, and iPTH(r=0.610, 0.640, 0.548, 0.404, P＜0.05). 
Conclusion  The serum level of SOST in patients with CKD stage 3-5 is increased with the increase of clinical stage, and is closely related to BMD and bone mineral metabolism indexes, such as Ca, P, Ca·P, iPTH and 25-（OH）D3, suggesting that it can be used as a reliable index to predict CKD-MBD.

Key words: nephrosis, osteosclerotic protein, mineral and bone disorder