Figure 2
Smallest classification tree of the EA patients according with their antibody status in which the anti-CarP antibodies appear. This tree is not a valid classification tool, it is only an exploratory analysis of the role of anti-CarP antibodies. Each of the antibodies was considered as negative, low positive and high positive in an ordinal scale. The tree was allowed to grow until more than 15 RA and 15 non-RA patients remained to classify in any of the two groups, which was the smallest tree showing a split based on anti-CarP antibodies. Node lines are dotted, except for terminal nodes that show continuous lines. Nodes include histograms with the frequencies of the RA (discontinuous lined bar) and non-RA (continuous lined bar) patients at that level of the tree. The antibody used for each split is indicated under parent nodes. Over each child node appears the rule to reach it and the number of patients arriving to it.
