IGFBP4 and type 2 diabetes mellitus: Circulating IGFBP4 was significantly higher in patients with DN (0.63 ± 0.09 μg/ml) compared to patients with T2D (0.28 ± 0.05 μg/ml, P = 0.002) and control (0.29 ± 0.03 μg/ml, P = 0.004, Figure 1(c)).