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Table 3 Comparing three models in model performance for 60-day hospital mortality in the derivation and validation dataset and for 60-day ICU mortality in the whole dataset

From: Risk factors for and prediction of mortality in critically ill medical–surgical patients receiving heparin thromboprophylaxis

Model performance Goodness-of-fit C index SMR (95 % CI)
p valuea AIC
Hospital mortality—derivation set (n = 1891)
 Model 1 (including APACHE II scores only) 0.68 5704 0.58 1.003 (0.959–1.050)
 Model 2 (including the other risk factors only)b 0.16 5359 0.62 1.002 (0.956–1.049)
 Model 3 (including both the other risk factors and APACHE II scores)c 0.90 5329 0.64 1.006 (0.961–1.052)
Hospital mortality—validation set (n = 1855)
 Model 1 (including APACHE II scores only) 0.37 5912 0.60 0.933 (0.890–0.978)
 Model 2 (including the other risk factors only)b 0.80 5765 0.59 1.019 (0.972–1.067)
 Model 3 (including both the other risk factors and APACHE II scores)c 0.88 5567 0.64 1.011 (0.966–1.060)
ICU mortality—the whole set (n = 3746)
 Model 1 (including APACHE II scores only) 0.75 8180 0.61 1.003 (0.972–1.036)
 Model 2 (including the other risk factors only)d 0.24 7821 0.58 1.001 (0.969–1.034)
 Model 3 (including both the other risk factors and APACHE II scores)e 0.74 7778 0.64 1.004 (0.972–1.038)
  1. AIC Akaike information criterion, SMR standardized mortality ratio
  2. aBased on Groennesby and Borgan test
  3. bThe other risk factors included BMI, medical admission, inotropes or vasopressors and acetylsalicylic acid or clopidogrel
  4. cModel 3 consisted of BMI, medical admission, inotropes or vasopressors, acetylsalicylic acid or clopidogrel, APACHE II score and the interaction between BMI and APACHE II score
  5. dThe other risk factors included BMI, medical admission and invasive mechanical ventilation
  6. eModel 3 consisted of BMI, medical admission, invasive mechanical ventilation and APACHE II score