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Table 3 Performance of classification tree, original SAPS II, and recalibrated SAPS II in all patients in the independent validation set (n = 2,289)

From: Identification of high-risk subgroups in very elderly intensive care unit patients

 

Classification tree

SAPS II

Recalibrated SAPS II

ROC-AUC ± SD

0.77 ± 0.01

0.77 ± 0.01

0.77 ± 0.01

Brier score

0.16

0.16

0.16

Threshold PPV

   

   0.5

0.69 (0.64–0.73)

0.68 (0.64–0.72)

0.71 (0.67–0.76)

Died (n)

329

340

305

Predicted to die (n)

480

502

427

   0.7

0.85 (0.8–0.89)

0.78 (0.73–0.82)

0.81 (0.76–0.86)

Died (n)

196

241

176

Predicted to die (n)

230

309

215

   0.8

0.88 (0.83–0.91)

0.83 (0.77–0.87)

0.88 (0.81–0.92)

Died (n)

184

168

119

Predicted to die (n)

210

203

136

  1. Confidence intervals (CIs) of differences between PPVs (asterisk indicates statistical significance at the 0.05 level) are as follows. For classification tree versus SAPS II, the CIs for cutoffs of 0.5, 0.7, and 0.8 are -0.032 to 0.047, 0.023 to 0.121*, and -0.006 to 0.104, respectively. For classification tree versus recalibrated SAPS II, the CIs for cutoffs of 0.5, 0.7, and 0.8 are -0.07 to 0.011, -0.027 to 0.086, and -0.057 to 0.055, respectively. For recalibrated SAPS II versus SAPS II, the CIs for cutoffs of 0.5, 0.7, and 0.8 are 0.056 to 0.016*, 0.072 to 0.004*, and 0.087 to 0.003*, respectively. PPV, positive predictive value; ROC-AUC, area under the receiver operating characteristic curve; SAPS II, Simplified Acute Physiology Score II; SD, standard deviation.
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Critical Care

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