Table 1Clinical and laboratory characteristics of the study subjects
Variable |
Value |
Number |
336 |
Age, yr |
58.6±12.3 |
Male sex |
217 (64.6) |
Body mass index, kg/m2
|
25.7±3.6 |
Waist circumference, cm |
90.4±9.4 |
Systolic BP, mm Hg |
136.9±17.8 |
Diastolic BP, mm Hg |
81.6±11.0 |
DM duration, yr |
9.9±8.5 |
HbA1c, % |
8.8±2.1 |
Glucose, mg/dL |
168.9±67.4 |
C-peptide, ng/mL |
2.1±1.2 |
ALT, U/L |
32.2±25.9 |
Creatinine, mg/dL |
1.1±0.2 |
eGFR, mL/min |
69.1±15.5 |
Total cholesterol, mg/dL |
172.8±46.0 |
Triglyceride, mg/dL |
143.4±95.0 |
HDL-C, mg/dL |
46.9±12.6 |
LDL-C, mg/dL |
102.9±39.3 |
Antidiabetic regimen |
|
Sulfonylurea |
177 (52.7) |
Metformin |
228 (67.9) |
Thiazolidinedione |
20 (6.0) |
α-Glucosidase inhibitor |
17 (5.1) |
Insulin |
106 (31.5) |
Table 2Blood levels of glucose, C-peptide, and intact incretin before and 30 minutes after ingestion of a standard mixed meal (n=336)
Variable |
Fasting levels |
30-min Postmeal levels |
P value |
Glucose, mg/dL |
168.9±67.4 |
257.4±69.4 |
<0.001 |
C-peptide, ng/mL |
1.89 (1.32–2.57) |
2.87 (1.95–4.06) |
<0.001a
|
iGLP-1, pmol/L |
4.86 (3.80–6.02) |
8.10 (6.23–13.20) |
<0.001a
|
iGIP, pmol/L |
2.68 (1.55–4.80) |
23.60 (18.24–26.52) |
<0.001a
|
Table 3Correlational analysis of the relationships between intact incretin levels and clinical and laboratory variables (n=336)
Variable |
Fasting iGLP-1, pmol/L |
ΔiGLP-1, pmol/L |
Fasting iGIP-1, pmol/L |
ΔiGIP, pmol/L |
Spearman's rho |
P value |
Spearman's rho |
P value |
Spearman's rho |
P value |
Spearman's rho |
P value |
Age, yr |
0.049 |
0.373 |
0.029 |
0.597 |
−0.010 |
0.858 |
−0.015 |
0.783 |
Body mass index, kg/m2
|
0.023 |
0.678 |
−0.040 |
0.461 |
0.033 |
0.547 |
0.030 |
0.590 |
Waist circumference, cm |
0.037 |
0.501 |
−0.063 |
0.260 |
0.023 |
0.674 |
−0.022 |
0.689 |
Systolic BP, mm Hg |
−0.026 |
0.638 |
−0.032 |
0.555 |
0.039 |
0.474 |
0.077 |
0.161 |
Diastolic BP, mm Hg |
−0.025 |
0.644 |
−0.003 |
0.957 |
0.013 |
0.808 |
0.061 |
0.262 |
DM duration, yr |
0.061 |
0.265 |
−0.079 |
0.149 |
−0.016 |
0.768 |
−0.116 |
0.034 |
HbA1c, % |
0.098 |
0.073 |
0.016 |
0.766 |
0.155 |
0.005 |
−0.184 |
0.001 |
Fasting glucose, mg/dL |
0.172 |
0.002 |
−0.040 |
0.466 |
0.214 |
<0.001 |
−0.106 |
0.054 |
ΔGlucose, mg/dL |
−0.127 |
0.021 |
0.013 |
0.816 |
−0.039 |
0.481 |
0.197 |
<0.001 |
Fasting C-peptide, ng/mL |
0.074 |
0.180 |
0.029 |
0.600 |
0.048 |
0.385 |
0.135 |
0.014 |
ΔC-peptide, ng/mL |
−0.086 |
0.117 |
0.154 |
0.005 |
−0.132 |
0.017 |
0.251 |
<0.001 |
ALT, U/L |
0.066 |
0.237 |
0.031 |
0.582 |
−0.011 |
0.840 |
0.077 |
0.164 |
Creatinine, mg/dL |
0.112 |
0.040 |
−0.072 |
0.190 |
−0.024 |
0.656 |
−0.036 |
0.509 |
eGFR, mL/min |
−0.138 |
0.012 |
0.029 |
0.600 |
−0.055 |
0.312 |
0.119 |
0.029 |
Total cholesterol, mg/dL |
0.042 |
0.445 |
0.067 |
0.223 |
−0.101 |
0.066 |
0.063 |
0.252 |
Triglyceride, mg/dL |
0.168 |
0.002 |
0.025 |
0.651 |
0.079 |
0.148 |
0.042 |
0.439 |
HDL-C, mg/dL |
−0.086 |
0.116 |
−0.012 |
0.822 |
−0.072 |
0.187 |
0.073 |
0.185 |
LDL-C, mg/dL |
0.048 |
0.379 |
0.042 |
0.447 |
−0.095 |
0.082 |
0.022 |
0.684 |
ΔiGLP-1, pmol/L |
0.017 |
0.750 |
- |
- |
- |
- |
- |
- |
ΔiGIP, pmol/L |
- |
- |
- |
- |
−0.159 |
0.003 |
- |
- |
Table 4Differences in intact incretin levels according to gender and the use of antidiabetic agents
|
Sex |
Use of sulfonylurea |
Use of metformin |
Use of thiazolidinedione |
Use of α-glucosidase inhibitor |
Use of insulin |
Male (n=217) |
Female (n=119) |
P value |
Yes (n=177) |
No (n=159) |
P value |
Yes (n=228) |
No (n=108) |
P value |
Yes (n=20) |
No (n=316) |
P value |
Yes (n=17) |
No (n=319) |
P value |
Yes (n=106) |
No (n=230) |
P value |
Fasting iGLP-1, pmol/L |
5.4±2.9 |
5.7±3.2 |
0.274 |
5.7±2.8 |
5.4±3.2 |
0.105 |
5.5±3.0 |
5.7±3.0 |
0.965 |
7.0±3.5 |
5.5±3.0 |
0.057 |
5.4±2.3 |
5.5±3.0 |
0.894 |
5.5±2.7 |
5.6±3.1 |
0.776 |
ΔiGLP-1, pmol/L |
5.0±6.4 |
4.8±6.0 |
0.812 |
4.9±6.2 |
4.9±6.3 |
0.427 |
5.2±6.3 |
4.4±6.2 |
0.893 |
4.0±5.8 |
5.0±6.3 |
0.377 |
4.7±4.6 |
4.9±6.3 |
0.928 |
4.6±6.0 |
5.0±6.4 |
0.726 |
Fasting iGIP-1, pmol/L |
3.5±3.2 |
4.4±4.6 |
0.128 |
3.8±3.4 |
3.9±4.2 |
0.977 |
3.9±3.6 |
3.6±4.2 |
0.338 |
5.2±4.8 |
3.7±3.7 |
0.362 |
4.0±3.3 |
3.8±3.8 |
0.745 |
3.7±3.3 |
3.9±4.0 |
0.851 |
ΔiGIP, pmol/L |
18.4±6.4 |
16.4±7.6 |
0.022 |
17.6±6.9 |
17.7±6.9 |
0.890 |
17.7±6.8 |
17.5±7.0 |
0.816 |
18.4±5.0 |
17.6±7.0 |
0.989 |
15.6±7.8 |
17.8±6.8 |
0.242 |
16.2±7.1 |
18.4±6.7 |
0.004 |
Table 5Multiple linear regression analyses predicting intact incretin levels
Dependent variables |
Independent variables |
β |
P value |
Fasting iGLP-1, pmol/L (R2=0.073) |
Age, yr |
0.067 |
0.275 |
Male sex |
−0.022 |
0.679 |
Fasting glucose, mg/dL |
0.202 |
<0.001 |
eGFR, mL/min |
−0.110 |
0.070 |
Triglyceride, mg/dL |
0.102 |
0.060 |
∆iGLP-1, pmol/L (R2=0.039) |
Age, yr |
0.036 |
0.505 |
Male sex |
0.010 |
0.859 |
∆C-peptide, ng/mL |
0.194 |
<0.001 |
Fasting iGIP, pmol/L (R2 =0.119) |
Age, yr |
−0.075 |
0.159 |
Male sex |
−0.078 |
0.145 |
HbA1c, % |
0.105 |
0.101 |
Fasting glucose, mg/dL |
0.020 |
0.754 |
Fasting C-peptide, ng/mL |
0.197 |
<0.001 |
∆iGIP, pmol/L (R2 =0.147) |
Age, yr |
0.018 |
0.769 |
Male sex |
0.063 |
0.237 |
DM duration, yr |
−0.056 |
0.382 |
HbA1c, % |
−0.049 |
0.407 |
∆Glucose, mg/dL |
0.127 |
0.023 |
∆C-peptide, ng/mL |
0.142 |
0.015 |
Use of insulin |
0.062 |
0.300 |
Fasting iGIP, pmol/L |
−0.058 |
0.334 |