Correlation of Fgf23 and Balp with Bone Mineral Density in Hemodialysis Patients

Chronic kidney disease (CKD) is associated with numerous complications such as bone mineral disorder. The aim of our study was to analyze the correlation of bone turnover markers with Bone Mineral Density (BMD) measurements in Tunisian end stage renal diseases (ESRD) patients.

This study included 100 ESRD Tunisian patients. Their estimated glomerular filtration rate (eGFR) was < 15 mL × min^-1 × (1.73 m²)^-1, which requires hemodialysis. Bone-specific alkaline phosphatase (BALP) serum concentration was determined with a chemiluminescence immunoassay. Fibroblast Growth Factor 23 (FGF23) serum was assessed by Enzyme-Linked Immunosorbent Assay method. The serum levels of 25-Hydroxyvitamin D (25(OH)D), intact parathyroid hormone (iPTH) and Beta cross-laps (CTX) was measured by Electrochemiluminescence Technology. DEXA (dual-energy x-ray absorptiometry) technique was used to evaluate BMD.

We observed a statistically significant negative correlation between BALP levels and total body BMD (r = -0.268; P = 0.015) particularly in femoral neck (FN) (r = -0.219; P = 0.037). BALP concentrations were negatively associated with total BMD especially in FN for patients with BMI < 30, FGF23 concentrations were also negatively correlated with BMD in lumbar spine site (LS) (r = -0.209; P = 0.046). For osteopenic patients we found an inverse correlation between 25(OH)D concentrations and BMD in LS position (r = -0.336; P = 0.038). In men group, we have also found a negative correlation between iPTH and total BMD (r = -0.326; P = 0.015). However we found a positive correlation between calcium expression and BMD in LS site (r = 0.270; P = 0.031).

FGF23 and BALP can predict bone loss in ESRD through their strong correlation with BMD in LS and FN sites respectively.