Table 3.
Sensitivities and specificities around 95, 97.5 and 100 % for diagnosing GDM with corresponding cut-offs for HbA1c and probabilities for GDM estimated by logistic regression models
| Outcome | HbA1c alonea | Model | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cut-off, HbA1c ≥ (%) | Sensitivity (%) | Specificity (%) | Percentage of women avoiding OGTT | Percentage of women avoiding OGTT misclassified | Cut-off, probability of GDM ≥ | Sensitivity (%) | Specificity (%) | Percentage of women avoiding OGTT | Percentage of women avoiding OGTT misclassified | |
| GDM-WHO week 32–36 | 4.7 | 100 | 3.7 | 3.4 | 0 | 0.009 | 100 | 8.5 | 8.0 | 0 |
| 4.8 | 97.3 | 8.0 | 7.7 | 2.0 | 0.011 | 97.3 | 11.2 | 10.7 | 1.5 | |
| 4.9 | 91.9 | 17.1 | 16.6 | 2.8 | 0.013 | 94.6 | 14.3 | 13.8 | 2.3 | |
| 5.5 | 29.7 | 95.0 | 6.4 | 73.2 | 0.16 | 29.7 | 95.0 | 6.4 | 73.2 | |
| 5.6 | 21.6 | 97.7 | 3.4 | 63.3 | 0.22 | 21.6 | 97.7 | 3.4 | 63.3 | |
| 5.9 | 0 | 100 | 0 | 0 | 0.50 | 0 | 100 | 0 | 0 | |
| GDM-WHO throughout pregnancy | 4.4 | 100 | 0.5 | 0.5 | 0 | 0.018 | 100 | 2.9 | 2.7 | 0 |
| 4.5 | 97.6 | 2.4 | 2.4 | 6.7 | 0.026 | 97.6 | 11.2 | 10.6 | 1.5 | |
| 4.6 | 95.2 | 7.7 | 7.5 | 4.3 | 0.027 | 95.2 | 11.8 | 11.3 | 2.8 | |
| 5.2 | 14.3 | 95.2 | 5.4 | 82.4 | 0.15 | 19.1 | 95.1 | 5.9 | 78.4 | |
| 5.3 | 9.5 | 97.8 | 2.7 | 76.4 | 0.18 | 16.7 | 97.4 | 3.5 | 68.6 | |
| 5.8 | 0 | 100 | 0 | 0 | 0.37 | 2.4 | 100 | 0.2 | 0 | |
| GDM-IADPSG week 18–22b | 4.7 | 100 | 16.6 | 16.2 | 0 | 0.010 | 100 | 16.0 | 15.7 | 0 |
| 4.8 | 87.5 | 30.3 | 29.8 | 1.0 | 0.0153 | 93.8 | 36.0 | 35.3 | 0.4 | |
| 4.9 | 68.8 | 51.3 | 50.8 | 1.5 | 0.0154 | 87.5 | 36.5 | 35.9 | 0.8 | |
| 5.2 | 12.5 | 94.7 | 5.5 | 94.6 | 0.056 | 18.8 | 95.0 | 5.3 | 91.7 | |
| 5.3 | 6.3 | 97.4 | 2.7 | 94.5 | 0.067 | 0 | 97.4 | 2.5 | 100 | |
| 5.8 | 0 | 100 | 0 | 0 | 0.18 | 0 | 100 | 0 | 0 | |
| GDM-IADPSG week 32–36b | 4.6 | 100 | 1.0 | 1.0 | 0 | 0.003 | 100 | 2.0 | 1.9 | 0 |
| 5.0 | 96.6 | 31.4 | 30.1 | 0.5 | 0.013 | 96.6 | 23.9 | 23.0 | 0.7 | |
| 5.1 | 82.8 | 48.2 | 46.7 | 1.7 | 0.018 | 93.1 | 36.0 | 34.6 | 0.9 | |
| 5.5 | 31.0 | 94.7 | 6.5 | 77.9 | 0.13 | 37.9 | 95.0 | 6.5 | 73.2 | |
| 5.6 | 20.7 | 97.5 | 3.3 | 71.4 | 0.18 | 24.1 | 97.5 | 3.5 | 68.2 | |
| 5.8 | 6.9 | 100 | 0.3 | 0 | 0.57 | 3.5 | 100 | 0.2 | 0 | |
| GDM-IADPSG throughout pregnancyb | 4.4 | 100 | 0.5 | 0.5 | 0 | 0.014 | 100 | 3.3 | 3.0 | 0 |
| 4.6 | 97.8 | 2.4 | 2.4 | 6.6 | 0.027 | 97.8 | 16.6 | 15.6 | 1.0 | |
| 4.7 | 95.6 | 16.5 | 15.6 | 2.0 | 0.037 | 95.6 | 30.0 | 28.2 | 1.1 | |
| 5.2 | 13.3 | 95.2 | 5.4 | 82.3 | 0.18 | 26.7 | 95.0 | 3.2 | 75.2 | |
| 5.3 | 8.9 | 97.8 | 2.7 | 76.2 | 0.21 | 11.1 | 97.4 | 6.5 | 70.7 | |
| 5.8 | 0 | 100 | 0 | 0 | 0.52 | 0 | 100 | 0 | 0 | |
See Table 2 for variables included in the various models. In addition, the percentage of women avoiding an OGTT by using cut-offs with high specificity to rule-in and high sensitivity to rule-out GDM and the percentage of those avoiding OGTT who are misclassified are shown
aHbA1c at gestational week 18–22 was used for GDM-WHO throughout pregnancy, GDM-IADPSG at week 18–22 and GDM-IADPSG throughout pregnancy, while HbA1c at gestational week 32–36 was used for GDM-WHO at week 32–36 and GDM-IADPSG at week 32–36
bModified IADPSG criteria were used, i.e. 1-h s-glucose was missing