GCG and diabetes mellitus: While previous studies focused primarily on hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), homeostasis model assessment of insulin resistance (HOMA-IR), advanced glycation end products (AGEs), and glucagon-like peptide 1 (GLP-1) to assess the severity of diabetes-related vascular complications [1–5], blood glucose variability has been recognized as another important measure in recent investigations [8–10].