The relationship between serum cystatin C level and insulin resistance in elderly patients with type 2 diabetes

Objective To study the relationship between serum cystatin C(Cys C)level and the development of insulin resistance(IR)in elderly patients with type 2 diabetes mellitus(T2DM). Methods A cross-sectional survey research involving 757 elderly patients with T2DM was performed and patients were divided into groups according to Cys C and IR levels.Serum 1evels of fasting insulin(FBI), fasting blood glucose(FPG), fasting C-peptide(FCP), glycosylated hemoglobin A1c(HbA1c), homeostasis model assessment of insulin resistance(IR)(HOMA2-IR-C), homeostasis model assessment of insulin secretion, homeostasis model assessment of insulin sensitivity(HOMA2-%S-C), micro-albuminuria(mALB)and serum lipid were measured and compared among the groups.Possible influence factors were adjusted, and the correlation between Cys C levels and IR was analyzed.The influencing factors on IR were also analyzed. Results There were statistically significant differences in ages, course of T2DM, FBI, FCP, HbA1c, urinary mALB, IR, insulin secretion, insulin sensitivity, morbidity rate of coronary heart disease, hypertension and diabetic nephropathy among the three groups(allP<0.05). Insulin sensitivity was decreased with the increase of Cys C level, while others were increased.Among 757 patients, the level of serum Cys C was positively correlated with FCP, HOMA2-IR-C levels, and was negatively correlated with HOMA2-%S-C levels(P<0.05). Multiple logistic regression analysis showed that the higher level of Cys C was independent risk factors for IR in elderly T2DM patients(OR=3.41, 95%CI: 2.22-5.22, P<0.05). Conclusions Serum Cys C level is closely related with IR in elderly T2DM, and the elevated level of serum Cys C is one of independent risk factors for elderly T2DM. Key words: Type 2 diabetes mellitus; Cysteine proteinase inhibitors; Insulin resistance