Basal and Postglucagon C-Peptide Levels in Ethiopians with Diabetes

Abstract

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.