In our subgroup analysis, the expression level of HLA-A29.1, MMP9, ANPEP, HDC, G-CSF3R, and STAT3 genes in both CRPS group and CRPS II subgroup was statistically different (as assessed by the 2−ΔΔCt value) compared to that of the control group. Here, STAT3 is linked to complex regional pain syndrome.