Insulin sensitivity assessed using urine C peptide creatinine ratio (UCPCR) in pregnancy: cross-sectional analysis of an English multiethnic cohort

AIMS: To assess urinary C peptide creatinine ratio (UCPCR) used in a modified Matsuda equation to measure insulin sensitivity (IS) in pregnancy. RESEARCH AND DESIGN METHODS: In this cross-sectional study, two IS measurements were calculated in 73 pregnant women at ~28 weeks of gestation by two separate methods using modified Matsuda equations. The first using the 0 and 120 min serum C peptide concentration during a 75 g oral glucose tolerance test (OGTT) and the second using the 0 and 120 min UCPCR values. The calculated IS measurements from the two methodologies were evaluated using Person’s test and linear regression analysis. The relationship between IS(OGTT) UCPCR and the fasting second void UCPCR and 120 min UCPCR was assessed using Pearson correlation and linear regression analysis after logarithmic transformation of the variables. Statistical analysis was performed using SPSS V.22. RESULTS: The IS measured using serum C peptide (IS(OGTTc-pep)) in the modified Matsuda equation correlated with the IS measurement using serum UCPCR (IS(OGTT-UCPCR)) (r 0.704, p<0.0001). A strong correlation was found between the IS(OGTT-UCPCR) and the fasting UCPCR (r −0.916, p<0.0001), displaying a hyperbolic relationship. CONCLUSION: The UCPCR provides a practical methodology to assess IS and β-cell function in pregnancy.