Table 2. Biochemical response to metformin.
| Visit 1 a | Visit 2 a | Paired difference Mean (95% CI) | P-value b | |
|---|---|---|---|---|
| Glucose (mmol/L) | 5.27 ± 1.06 | 5.08 ± 0.94 | -0.20 (-0.31, -0.08) | 0.0008 |
| Took any metformin | 5.27 ± 1.07 | 5.04 ± 0.89 | -0.23 (-0.34, -0.11) | 0.0002 |
| Took no metformin | 5.42 ± 0.08 | 5.85 ± 1.48 | 0.44 (-0.28, 1.15) | 0.22 |
| Insulin (pmol/L) | 36.12 [22.62, 61.46] | 29.97 [17.36, 57.60] | -0.16 (-0.26, -0.05) | 0.003 |
| Took any metformin | 36.18 [22.76, 61.65] | 29.37 [17.21, 56.48] | -0.19 (-0.29, -0.08) | 0.0006 |
| Took no metformin | 30.03 [17.22, 55.04] | 51.87 [27.44, 86.62] | 0.44 (-0.91, 0.03) | 0.07 |
| HOMA-IR (mmol*pmol/L2) | 8.31 [4.99, 14.29] | 6.49 [3.60, 13.22] | -0.20 (-0.30, -0.09) | 0.0004 |
| Took any metformin | 8.31 [4.99, 14.33] | 6.31 [3.50, 12.70] | -0.23 (-0.34, -0.12) | <0.0001 |
| Took no metformin | 8.33 [4.12,12.24] | 13.19 [5.93, 27.88] | 0.50 (-0.02, 1.03) | 0.06 |
| Glucagon (ng/L) | 26.00 [17.00, 37.00] | 26.00 [17.00, 36.00] | 0.02 (-0.06, 0.02) | 0.32 |
| Took any metformin | 26.00 [17.00, 36.00] | 26.00 [17.00, 36.00] | -0.02 (0.06, 0.02) | 0.35 |
| Took no metformin | 32.00 [22.00, 46.00] | 24.00 [19.00, 42.00] | -0.04 (-0.26, 0.17) | 0.68 |
| Proinsulin (mmol/L) | 14.0 [8.70, 24.25] | 12.25 [7.70, 22.00] | -0.12 (-0.16, -0.08) | <0.0001 |
| Took any metformin | 13.75 [8.45, 24.00] | 12.00 [7.53, 21.00] | -0.13 (-0.17, -0.09) | <0.0001 |
| Took no metformin | 17.50 [13.38, 29.25] | 18.00 [11.75, 30.75] | 0.07 (-0.08, 0.21) | 0.33 |
Values are shown at Visit 1 and Visit 2 for all participants and stratified by those participants who took no or any number of (1, 2, 3, or 4) metformin pills.
a The mean ± SD for glucose and median [interquartile range] for non-normally distributed measures (insulin, HOMA-IR, glucagon, and proinsulin) are shown at Visit 1 and Visit 2. For statistical comparison, non-normally distributed data were log-transformed and paired difference for log-transformed measures is the mean of the log-transformed value at Visit 2 minus log-transformed value at Visit 1.
b P-value is for paired t-test for glucose and for log-transformed insulin, HOMA-IR, glucagon, and proinsulin.
SD: standard deviation. CI: confidence interval. HOMA-IR: homeostatic model assessment of insulin resistance.