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Table 7 Variables entered and removed (in square brackets) at each step of the stepwise selection procedure

From: A comparative analysis of predictive models of morbidity in intensive care unit after cardiac surgery – Part II: an illustrative example

Step no. BL BQ k NN LR HS DS ANN1 ANN2
1 O2ER O2ER Post-CI O2ER O2ER SvO2 O2ER O2ER
2 VCO2 DO2I O2ER VCO2 VCO2 Card-ID Card-ID VO2
3 Card-ID Card-ID Card-ID Card-ID Card-ID DO2I VO2 Card-ID
4 PVD PVD PVD PVD PVD O2ER PVD PVD
5 TBU W TBU TBU TBU PVD TBU Gly
6 EM VD MAP EM EM O2ER Pre-CI Gender
7 Pre-CI DAP   SAP SAP EM EM MVR
8 WBC SAP   Pre-CI Pre-CI BSA WBC Cr
9 SAP Diur   WBC WBC AD Age AVO2
10 Age Xclamp   SaO2 SaO2 CHF SaO2 Arrhy
11 PvO2 H   PvO2 PvO2 MVR AD  
12 SaO2 Gender   AD AD O2ER P/F  
13 AD    PaO2 PaO2 MR PVS  
14 SvO2    Cr Cr EM Temp  
15 Xclamp    CvO2 CvO2 Card-ID   
16 PaO2    Xclamp Xclamp O2ER   
17 [PvO2]    DO2I DO2I PVD   
18 Cr    W W Diab   
19 Intra-CI    SVRI SVRI VCO2   
20 Post-CI    [VCO2] [VCO2] O2ER   
21 [Age]    Pre-IABP Pre-IABP AD   
22 W    CHF CHF O2ER   
23 [Pre-CI]    [Xclamp] [Xclamp] CHF   
24 DO2I      CABG-C   
25 [VCO2]      MR   
26 Bil      PAH   
27 Hb      O2ER   
28 [WBC]      IABP   
29 SVRI      O2ER   
30 [Post-CI]      IABP   
31 BSA      O2ER   
32 CABG-A      PVS   
33       IABP   
34       O2ER   
35       IABP   
  1. BL, Bayes linear model; BQ, Bayes quadratic model; k NN, k-nearest neighbour model; LR, logistic regression model; HS, Higgins score system; DS, direct score system; ANN1, one-layer artificial neural network; ANN2, two-layer artificial neural network. Predictor variable abbreviations are indicated in Tables 1-6.