We found a positive correlation between the serum level of OGN with age (r = 0.226; p < 0.001), iPTH (r = 0.179; p = 0.042), and FGF-23 (r = 0.324; p < 0.001) and a negative correlation with eGFR (r = −0.189; p = 0.027) in T2D patients (Figure 2). This evidence concerns the gene FGF23 and type 2 diabetes mellitus.