Connecting peptide (c-peptide) and the duration of diabetes mellitus amongst patients, at the Federal Medical Centre (FMC), Owerri, southeast, Nigeria
Objective: C-peptide is derived from proinsulin and it is secreted in equimolar concentration with insulin. Plasma C-peptide is more stable than insulin and it provides an indirect measure of insulin secretory reserve and beta cell function. To determine relationship between C-peptide and duration of diabetes mellitus, age, body mass index, systolic blood pressure and diastolic blood pressure.
Methods: This is a cross-sectional study of type 2 diabetes mellitus patients attending Endocrine Clinic. Information such as age, sex, height, weight, blood pressure and duration of diabetes were obtained. Blood samples were taken for fasting serum C-peptide. Data was analysed using SPSS version 16.
Results: Out of the 46 subjects recruited 23 (50%) were females and 23 (50%) were males. The mean age was 55.63 ± 14.7 years. Mean duration of diabetes for both sexes was 8 years with a range of 1 to 32 years. The mean BMI was 26.87 ± 5.00 kg/m2for males and 30.09 ± 4.32 Kg/m2 for females. The mean fasting serum C-peptide was 2.16 ± 1.41 ng/ml and there was no significant difference between males and females. There is statistically significant inverse correlation between C-peptide and duration of diabetes (r= -0.356, p= 0.015). Conversely there is a direct relationship between C-peptide and BMI (r=0.307, p=0.038).
Conclusion: Increasing duration of diabetes is associated with decreasing level of C-peptide and decreased beta cell secretory reserve