Fig. 2

Inability of clinical and biological parameters to predict response to abatacept/methotrexate (ABA/MTX). Two independent statistical methods were performed to identify variables to predict drug response in subset 1. Next, the prediction accuracy of these variables was evaluated in subset 2. a In subset 1, four variables were selected by logistic regression: C-reactive protein (CRP), tender joint count, MTX dose and disease duration. In subset 2, these four variables allowed good categorization of 12 out of 19 responders (R) and 6 out of 13 non-responders (NR). The remaining 14 patients were misclassified. b In subset 1, linear discriminant analysis was performed to balance each parameter by calculation of the coefficient of linear discriminant analysis. In subset 2, these data allowed good categorization of 13 out of 19 R and 6 out of 13 NR. The remaining 13 patients were misclassified. DAS28 disease activity score in 28 joints, Sen sensitivity, Spe specificity, PPV positive predictive value, NPV negative predictive value