This study aims to investigate whether the levels of the soluble receptors sRAGE, sRANKL, and OPG are affected by the distribution of RA patients in subgroups according to soluble transferrin receptor/log ferritin (sTfR-F index) and hemoglobin (Hb) levels and to examine their correlation with indicators of iron metabolism, disease activity, and autoimmune and inflammatory changes. The gene discussed is GSTM1; the disease is rheumatoid arthritis.