Pain intensity evaluation
Visual analog scale (VAS) scores obtained at baseline, during and after 24 weeks in the group treated with um-PEA as add-on to tapentadol (um-PEA-TP group) or with tapentadol only (TP-group). Data are means ± S.E. Both groups showed a significant reduction in low back pain intensity over time (p < 0.0001). A further, significant difference (p < 0.0001) between the two groups was found in favor of the um-PEA-TP group. Statistical analysis were performed with GLMM.