Urinary C-Peptide Secretion(UCPS): Can It be A New Index to Reflect Insulin Sensitivity and A Predictor in Pregnant Women?

Abstract Background: In order to assess the correlation between pregnant women's urinary C-peptide secretion(UCPS) and insulin sensitivity, and to examine the predictors of gestational diabetes. Methods: we recruited 166 women between 20 and 28 weeks of gestation. Their height and weight were measured to calculate the body mass index (BMI). 75g OGTT was carried out, so as to detect the serum glucose, serum insulin and C-peptide levels. Besides, the homeostasis model assessment of insulin resistance (HOMA-IR), homeostasis model assessment of β cell function (HOMA-β), Matsuda index, and area under the serum C-peptide curve (CPauc) were calculated. Additionally, the fasting urine specimen and all urine samples within 2 hours after OGTT were collected to determine the urinary C-peptide and urine volume to calculate UCPS. Results: We found that Fasting serum insulin (Fins), Fasting serum C-peptide (FCP), BMI, OGTT 2h UCPS(UCPS120), CPauc, Matsuda index and HOMA-IR of GDM group were higher than NGT group. FCP was correlated with UCPS0 (r=0.234, p=0.002) and HOMA-β(r=0.251, p=0.001). UCPS120 was correlated with CPauc(r=0.176 p<0.001), Matsuda index(r=-0.362, p<0.001) and HOMA-IR(r=0.336, p<0.001). The combination of BMI and UCPS120 was better than other index in predicting GDM, with a sensitivity of 72.0% and specificity of 70.7%. Conclusion: UCPS120 had the potential to be a new index to reflect insulin sensitivity in pregnant women. To screening the GDM, the combination of BMI and UCPS120 was better than other index.