Table 2.
Fasting and stimulated C-peptide concentrations
| TrialNet |
ECPT |
|||
|---|---|---|---|---|
| MMTT | GST | MMTT | GST | |
| n | 143 | 135 | 116 | 117 |
| Tests | 278 | 271 | 174 | 174 |
| Fasting (pmol/ml) | 0.17 (0.14–0.19) | 0.17 (0.15–0.20) | 0.07 (0.05–0.08) | 0.07 (0.05–0.08) |
| Peak stimulated (pmol/ml) | 0.40 (0.38–0.42) | 0.30 (0.28–0.32)* | 0.13 (0.12–0.15) | N/A |
| 90-min MMTT/6-min GST (pmol/ml) | 0.36 (0.34–0.38) | 0.27 (0.25–0.28)* | 0.12 (0.11–0.13) | 0.10 (0.09–0.10)* |
| AUC mean (pmol/ml) | 0.31 (0.29–0.33) | 0.25 (0.24–0.26)* | 0.11 (0.10–0.11) | N/A |
Data are geometric means (95% CI). Geometric means, calculated as exp[mean log(x)], are from a mixed-model analysis of the log(C-peptide) adjusted for fasting glucose concentration, age, sex, continuous diabetes duration, test order, and sequence group. Analyses of stimulated values were also adjusted for basal log(C-peptide). Analyses were conducted separately for TrialNet and EPCT.
*
P < 0.0001 for the comparison between the TrialNet GST and MMTT. N/A, not applicable.