Background: Red blood cell distribution width (RDW) has been reported as a marker for inflammation and tumors. The present study aims to investigate the use of RDW in patients with multiple myeloma (MM).
Methods: Seventy-three patients with newly diagnosed symptomatic multiple myeloma (SMM), 39 patients with relapsed multiple myeloma (RMM), and 91 healthy individuals were recruited into this study. The demographic and laboratory parameters were reviewed retrospectively, and the correlation between RDW and other parameters among groups were evaluated by Spearman’s correlation analysis. The sensitivity and specificity of RDW were determined by receiver operating characteristic (ROC) curve analysis.
Results: The RDW values in both SMM and RMM were significantly higher than in the healthy individuals (p < 0.001). In SMM patients with International Staging System (ISS) Stages II and III, the level of RDW was higher than in the patients with ISS Stage I; however, there was no significant difference between each ISS stage in RMM patients. The RDW strongly correlated with platelet distribution width (PDW), cystatin C, serum beta2-microglobulin (Sβ2M), hemoglobin (HGB), hematocrit (HCT), albumin (Alb), and calcium (p < 0.05) in SMM patients, and RDW in RMM patients had a positive or negative correlation with PDW, Sβ2M, globulin, HGB, absolute neutrophil count, platelet count, HCT, and Alb (p < 0.05). The ROC curve analysis showed that RDW > 13.5 had 94.5% sensitivity and 63.7% specificity for SMM, and 92.3% sensitivity and 63.7% specificity for RMM. Conclusions: Elevated RDW in MM patients was associated with the stage of the disease.