Correlation between plasma strontium concentration and calcium and phosphorus metabolism in patients with diabetic nephropathy

Objective To explore the relationship between concentration of plasma strontium (Sr²⁺) and parameters of calcium and phosphorus metabolism in patients with diabetic nephropathy. Methods A total of 500 patients with diabetic nephropathy treated in the 163th Hospital of the People's Liberation Army from May 2014 to February 2018 were selected. The clinical data and serum biochemical indicators of the patients were collected, and the patients were classified into different stages of chronic kidney disease (CKD)stages based on estimated glomerular filtration rate (eGFR):CKD stages 1~2, stage 3 and stages 4~5. Multiple linear regression analysis was used to investigate the relationship between plasma Sr²⁺ concentration and calcium-phosphorus metabolism. Results The median concentration of plasma Sr²⁺ was 269 nmol/L, which was within the normal range. The plasma Sr²⁺ concentration in the patients with CKD stages 1~2 was 246 nmol/L; the plasma Sr²⁺ concentration in patients with CKD stage 3 was 347 nmol/L; the plasma Sr²⁺ concentration in the patients with CKD stages 4~5 was 419 nmol/L. With the multivariate analysis, plasma Sr²⁺concentrations were found to be independently associated with eGFR (β=-0.411, P<0.01)and plasma fibroblast growth factor 23(FGF23) concentrations (β=0.088, P<0.01). Conclusions In patients with diabetic nephropathy, plasma Sr²⁺ concentration has negative correlation with eGFR, and is independently associated with plasma FGF23 concentration.