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clinmed/2003070002v1 (February 25, 2004)
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Breaking the paradigm: Scores are of no clinical relevance for predicting outcome in abdominal septic shock patients
Jürgen Paetz, Björn Arlt, Katharina Holzer, Rüdiger Brause, Albrecht Encke, and Ernst Hanisch
Purpose of the study
Scores are widely used for predicting outcome in critically ill patients. This study addresses two questions: 1. How do scores perform in abdominal septic shock patients? and 2. Can the performance of scores be improved by using neural network models?
We compare the outcome performance of a neural network (NN) for different data sets with that of common scores (SOFA, APACHE II, SAPS II, MODS) by ROC analysis in 382 abdominal septic shock patients who were identified and documented prospectively.
ICU mortality is 49 %. In the first three days of the ICU stay, SOFA, APACHE II, SAPS II and MODS attain AUC values of 0.54 [95 % CI 0.41,0.60]; 0.52 [0.41,0.64]; 0.52 [0.46,0.58]; 0.52 [0.46,0.59], respectively. NN performs similarly (0.52 [0.46,0.58]). AUC values are high only in the last three days of the ICU stay (SOFA 0.89, [0.83,0.96], APACHE II 0.79 [0.70,0.89], SAPS II 0.85 [0.77,0.92], MODS 0.88 [0.77, 0.99] and NN 0.88, [0.83,0.92] ). With NN it is possible to attain a performance equivalent to that of the SOFA score by considering the three variables systolic and diastolic blood pressure and the number of thrombocytes only.
In patients suffering exclusively from abdominal septic shock, scores are of no clinical relevance for outcome prediction, since AUC values are very low in the early ICU period. A neural network analysis cannot improve this performance. Nevertheless, a neural network data analysis derived from the last three days of the ICU stay is generated as the basis of a new web-based alarm system, which is currently under evaluation in a randomised, prospective multicenter study.
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