INS and type 2 diabetes mellitus: Compared with T2DM patients with a UCPCR > 0.20 nmol/mmol, T2DM patients with UCPCR ≤ 0.20 nmol/mmol had a lower serum C-peptide (fasting C-peptide, 0.39 nmol/L vs. 0.66 nmol/L, P < 0.001; postprandial C-peptide, 0.93 nmol/L vs. 1.55 nmol/L, P < 0.001), lower BMI (22.8 kg/m2 vs. 25.2 kg/m2, P = 0.006), and higher percentage of insulin or secretagogue therapy (92.0% vs. 59.5%, P = 0.002).