Basal and postglucagon C-peptide levels in Ethiopians with diabetes

OBJECTIVE - To study basal C-peptide (BCP) and postglucagon C-peptide (PGCP) levels in Ethiopians with diabetes. RESEARCH DESIGN AND METHODS - A total of 56 subjects with type 1 diabetes, 97 subjects with type 2 diabetes, and 50 control subjects were recruited from a hospital in Ethiopia. BCP was determined in all subjects and PGCP in 86 subjects. RESULTS - Mean (±SEM) BCP, PGCP, and the increment after glucagon in type 1 diabetic subjects (0.14 ± 0.04, 0.22 ± 0.11, and 0.08 ± 0.05 nmol/l, respectively) were lower (P < 0.001) than those in type 2 diabetic subjects (0.66 ± 0.04, 1.25 ± 0.10, and 0.56 ± 0.06 nmol/l, respectively) or control subjects (0.54 ± 0.04, 1.52 ± 0.26, and 1.11 ± 0.24 nmol/l, respectively). The mean BCP level was higher in type 2 diabetic subjects than control subjects (P = 0.015), whereas the mean increment was lower (P = 0.005). Insulin-treated type 2 diabetic subjects, compared with non-insulin-treated type 2 diabetic subjects, had lower mean BCP (0.55 ± 0.08 nmol/l [n = 37] vs. 0.73 ± 0.04 [n = 60], P = 0.001), lower PGCP (0.97 ± 0.20 nmol/l [n = 18] vs. 1.40 ± 0.11 [n = 35], P = 0.010), and a lower C-peptide increment (0.34 ± 0.06 [n = 18] vs. 0.67 ± 0.07 nmol/l [n = 35], P = 0.003). In both the type 1 and type 2 diabetic groups, those with BCP levels <0.2 nmol/l had lower BMI than those with higher BCP levels (P = 0.023 and P < 0.001, respectively). CONCLUSIONS - Combined with clinical criteria, C-peptide levels are good discriminators between type 1 and type 2 diabetes in Ethiopians and may also be useful in identifying subjects with type 2 diabetes who require insulin therapy. There is a subgroup of type 2 diabetic subjects with features of type 1 diabetes.