Fig. 2

REPTree decision tree. Caption: The structure of this decision tree derives from the available data. Slight variations can lead to significant changes. Although it may reflect to some extend a clinical approach, it must be interpreted more as a model derived from the observed data rather than a definitive clinical rule. For further details on the amount of (in-) correctly classified instances from the training and pruning set refer to the supplement. REPTree = reduced error pruning tree