The levels of systolic blood pressure (SBP), diastolic blood pressure (DBP), FBG, HbA1c, TC, TGs, UACR, cystatin C and miR‐29a in the T2DM patients were significantly higher than those in the control subjects (p < 0.05), while eGFR in the T2DM patients was significantly lower than that in the control subjects (p < 0.05). The gene discussed is CST3; the disease is type 2 diabetes mellitus.