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Measures of discrimination and calibration for APACHE II in obstetric and non-obstetric admissions |
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| All obstetric admissions (n = 1565) |
Direct obstetric admissions (n = 1216) |
Indirect or coincidental obstetric admissions (n = 349) |
Female nonobstetric admissions aged 16–50 years (n = 18,450) |
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| Discrimination (AUC [95% CI]) |
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| APACHE II scorea |
0.839 (0.820 to 0.857) |
0.819 (0.795 to 0.840) |
0.839 (0.797 to 0.876) |
0.812 (0.807 to 0.818) |
| APACHE II probabilitya |
0.810 (0.790 to 0.829) |
0.737 (0.711 to 0.761) |
0.806 (0.760 to 0.845) |
0.855 (0.850 to 0.860) |
| Calibration |
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| Mortality ratio (95% CI) |
0.245 (0.167 to 0.346) |
0.214 (0.120 to 0.352) |
0.282 (0.163 to 0.453) |
0.907 (0.878 to 0.937) |
| Hosmer–Lemeshow |
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| C statistic (P value) |
166 (< 0.001) |
101 (<0.001) |
47 (<0.001) |
69 (<0.001) |
| Cox's regression calibration |
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| Slope (95% CI) |
0.728 (0.491 to 0.966) |
0.570 (0.277 to 0.863) |
0.937 (0.509 to 1.37) |
1.05 (1.01 to 1.08) |
| Intercept (95% CI) |
-2.09 (-2.60 to -1.59) |
-2.57 (-3.39 to -1.76) |
-1.69 (-2.33 to -1.05) |
-0.120 (-0.179 to -0.061) |
| χ2(2) (P value)a |
140 (<0.001) |
87 (<0.001) |
55 (<0.001) |
57 (<0.001) |
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aχ2 statistic with two degrees of freedom (and associated P value) from a likelihood ratio test of slope 1 and intercept 0 in Cox's regression calibration model. APACHE, Acute Physiology and Chronic Health Evaluation; AUC, area under the receiver operating characteristic curve; CI, confidence interval. | ||||
Harrison et al. Critical Care 2005 9(Suppl 3):S25 doi:10.1186/cc3542 |
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