Circulating Levels of Soluble Klotho and Fibroblast Growth Factor 23 in Diabetic Patients and Its Association with Early Nephropathy

Introduction Diabetic nephropathy is a leading cause of chronic kidney disease (CKD). In diabetes, changes in serum levels of both soluble alpha Klotho (sKL) and fibroblast growth factor 23 (FGF-23) have been associated with CKD progression. Objective To evaluate the associations of circulating levels of sKL and FGF-23 with the presence of early nephropathy (EN) in diabetic patients. Methods A cross-sectional study in 136 Mexicans with type 2 diabetes mellitus (T2DM). Early nephropathy was defined as an estimated glomerular filtration rate (≥60 ml/min) and urinary albumin excretion (≥30 mg/g). Serum concentrations of sKL and FGF-23 were measured using ELISA. Associations were evaluated with multiple logistic regression. Results Fifty-two subjects had EN. Median values of sKL and FGF-23 for all individuals were 244 pg/mL (interquartile range [IQR]: 201-402) and 92 pg/mL (IQR: 39–507), respectively. A positive correlation was found between levels of sKL and FGF-23 ( r  = 0.38; p r  = 0.24; p p  = 0.02). Elevated concentrations of FGF-23 were negatively associated with EN (Odds Ratio [OR adjusted ] = 0.29, 95% Confidence Interval [95% CI] = 0.13, 0.65). Conclusions In Mexican diabetic patients, serum levels of FGF-23 were positively correlated with sKL but negatively correlated with ARB therapy. In addition, a higher concentration of FGF-23 reduced the odds of early nephropathy in patients with T2DM.