Association between serum cystatin C and bone turnover markers in elderly patients with different renal function

Xueyu LI; Yun ZHU; Fan ZHANG

ABSTRACT

Objective:

To observe the association between serum cystatin C(CysC)and bone turnover markers levels in elderly chronic kidney disease(CKD)patients with different estimated glomerular filtration rate(eGFR).

Methods:

A total of 74 elderly patients aged 61-97(79.5±8.7)years with 40 males, receiving serum CysC and bone turnover markers tests, were recruited in the Department of Geriatrics, Peking University Third Hospital from June 2019 to June 2020.They were divided into normal eGFR group(G1 and G2 stage)(eGFR≥60 ml·min -1·1.73 m -2, n=42)and decreased eGFR group(G3-G5 stage)(eGFR<60 ml·min -1·1.73 m -2, n=32). Serum levels of CysC and bone turnover markers[β-isomerized C-terminal telopeptides(β-CTX)and procollagen type I N-terminal propeptide(P1NP)]were tested.The association between CysC and bone turnover markers was analyzed.

Results:

The levels of β-CTX, P1NP and parathyroid hormone(PTH)were higher in decreased eGFR group(G3-G5 stage)than in normal eGFR group(G1 and G2 stage), and 25(OH)D3 was lower in decreased eGFR group(G3-G5 stage)than in normal eGFR group(G1 and G2 stage), but the differences were not statistically significant(all P>0.05). In decreased eGFR group(G3-G5 stage), CysC had significant association with β-CTX( r=0.598, P<0.01)and P1NP( r=0.519, P<0.01), respectively.In normal eGFR group(G1 and G2 stage), CysC was significantly related with P1NP( r=0.342, P<0.05), and CysC had no correlation with β-CTX( r=-0.030, P> 0.05). Multiple regression analysis showed that CysC was independently positively associated with P1NP in total 74 subjects( β=19.19, P<0.01), and in 21 osteoporosis patients( β=28.78, P<0.05).

Conclusions:

In elderly patients with moderate and severe renal dysfunction, a higher CysC level indicates higher bone turnovers.CysC is independently positively associated with the bone formation marker P1NP, suggesting CysC may reflect a bone protective effect in elderly patients with different renal function.