Relationship of C-peptide levels to duration of Type 1 diabetes – A study from Sindh, Pakistan

OBJECTIVE: To determine the relationship of C-peptide levels with duration of type 1 diabetes mellitus. METHODS: This prospective study was conducted at Baqai Institute of Diabetology and Endocrinology (BIDE), Baqai Medical University (BMU), Karachi-Pakistan from December 2013 to December 2015. A total of 184 subjects were recruited during the study period, 100 in Group-A and 84 in Group-B. Subjects clinically diagnosed with type 1 diabetes Mellitus (T1DM) were categorized into two groups based on duration of diabetes: Group-A (with ≤1-year duration of diabetes) and Group-B (with >1-year duration of diabetes). Ninety-nine of the 100 enrolled subjects in Group-A were diagnosed as having T1DM, with one subject who presented at 11.9 years of age and diagnosed with T2DM excluded from this study. Blood samples were drawn for biochemical parameters. Data for baseline characteristics and clinical parameters (HbA1c and C-peptide) were obtained from hospital management system of BIDE. RESULTS: Fifty-seven (57.6%) subjects in Group-A, and 39 (46.4%) in Group-B were males. Mean±SD duration of diabetes (years) was 0.64±0.6 (range 0-1) in Group-A, and 7.65±5.5 (range 1-23) in Group-B. Family history of T1DM and T2DM was 1(1%) and 27(27.3%) in Group-A, and 8(9.52%) and 21(25%) in Group-B, respectively. Twenty-one (21.2%) subjects presented in diabetic ketoacidosis (DKA) in Group-A and 18(21.4%), in Group-B. Mean±SD for HbA1c was non-significantly higher in Group-A 11.12±2.31 compared to Group-B 10.42±1.45. Mean±SD for C-peptide was 1.91±1.53 ng/mL (0.60±0.481 nmol/L) in Group-A, and 1.82±1.01 (0.57±0.32 nmol/L) in Group-B (p=0.984). CONCLUSION: The study found that subjects with longer duration of T1DM had non-significantly decreased C-peptide levels compared to a group in which C-peptide was measured at or soon after diagnosis. Furthermore, C-peptide levels in many subjects with longer duration were higher than expected in classic T1DM.