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Table 4 Order of Entry of Predictor Variables in the Final SURPAS Models and C-indexes and Brier Scores for the Development and Test Datasets in the Internal Validation Study

From: Refining the predictive variables in the “Surgical Risk Preoperative Assessment System” (SURPAS): a descriptive analysis

Characteristicsa 30-day Mortality Morbidity Unplanned Readmission Respiratory Infection UTI VTE Cardiac Bleeding Renal Stroke Average Rank
CPT-specific event rate 2 1 1 1 1 1 1 2 1 1 1 1.2
ASA class 1 2 2 2 3 2 3 1 2 2 2 2.0
Inpatient/outpatient 6 3 3 3 2 3 2 4 3 3 4 3.3
Primary surgeon specialty 7 4 4 6 4 4 6 6 4 4 5 4.9
Age (years) 4 7 7 7 6 5 4 3 5 7 3 5.3
Functional health status 3 5 5 4 7 6 5 7 8 6 6 5.6
Emergency operation 5 6 8 5 5 8 7 5 7 5 7 6.2
Work relative value unit 8 8 6 8 8 7 8 8 6 8 8 7.5
Model c-index 0.928 0.823 0.724 0.893 0.805 0.777 0.788 0.871 0.875 0.863 0.839  
Model Brier score 0.0103 0.0879 0.0485 0.0234 0.0438 0.0145 0.0086 0.0062 0.0406 0.0060 0.0021  
Validation c-index 0.931 0.823 0.724 0.893 0.805 0.776 0.790 0.877 0.876 0.870 0.875  
Validation Brier score 0.0102 0.0880 0.0483 0.0232 0.0437 0.0144 0.0086 0.0063 0.0407 0.0059 0.0020  
  1. aAbbreviations: ASA class American Society of Anesthesiology physical status classification, CPT Current Procedural Terminology, SURPAS Surgical Preoperative Risk Assessment System, UTI Urinary tract infection, VTE Venous thromboembolism