Figure 3.

Nonparametric receiver operating characteristics (ROC) analyses. The area under the curve (AUC) with exact binomial 95% confidence intervals (CIs) according to each step of hierarchical multiple regression analysis is presented in Table 4. The ROC shows the discriminant properties of the set of variables retained in each block. Variable retained in step I: analgesic use (four or more than 4 days per week) and heat pain threshold (HPT). Step II: step I along with catastrophizing pain (cutoff-Q₂₅ = 33), BDNF (cutoff-Q₇₅ = 58.11) and PSQI (cutoff-Q₂₅ > 17). Step III: step II along with the number of psychiatric diagnoses according to the MINI (major depressive episode with dysthymia, manic-depressive disorder and generalized anxiety disorder). Step IV: step III along with FIQ (cutoff-Q₇₅ = >78) to assess the impact of symptoms on quality of life.