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Table 3 Model fit – comparison of the SAPS II, APACHE II and ICNARC models

From: Admission factors associated with hospital mortality in patients with haematological malignancy admitted to UK adult, general critical care units: a secondary analysis of the ICNARC Case Mix Programme Database

 

SAPS II model

APACHE II model

ICNARC model

Eligible admissions, n (%)

4,973 (64.6)

6,212 (80.7)

7,156 (93.1)

Observed deaths

3,030

3,579

4,237

Expected deaths

2,675.2

3,538.5

3,393.3

SMR (95% CI)

1.13 (1.11 to 1.16)

1.01 (0.99–1.03)

1.25 (1.22 to 1.27)

AUROC (95% CI)

0.74 (0.73 to 0.75)

0.74 (0.73 to 0.76)

0.79 (0.78 to 0.80)

Hosmer–Lemeshow Ca statistic

   

   χ2(10)

568.0

68.0

900.9

   P value

< 0.001

< 0.001

< 0.001

Cox's calibration regression

   

   Intercept (95% CI)

0.44 (0.38 to 0.51)

0.08 (0.02 to 0.14)

0.62 (0.56 to 0.67)

   Slope (95% CI)

0.59 (0.54 to 0.63)

0.80 (0.75 to 0.85)

0.77 (0.73 to 0.81)

   χ2(2)

469.4

54.3

708.95

   P value

< 0.001

< 0.001

< 0.001

  1. The Hosmer-Lemeshow test divides the data into ten groups and compares the observed mortality in these groups to the predicted mortality given by the model. The C statistic is a chi-squared statistic for testing the hypothesis of perfect calibration. A significant value for the C statistic indicates that calibration is not perfect.
  2. APACHE II: Acute Physiology and Chronic Health Evaluation II; AUROC: area under the receiver operating characteristic curve; CI: confidence interval; ICNARC: Intensive Care National Audit and Research Centre; SAPS II: Simplified Acute Physiology Score II; SMR: standardised mortality ratio. a