High Red Blood Cell Distribution Width to Platelet Ratio is an Independent Poor Prognostic Factor in Patients with Newly Diagnosed Multiple Myeloma.

Background: The red blood cell distribution width to platelet ratio (RPR) is an inflammatory marker that is a convenient and reliable prognostic indicator for several solid malignancies. However, the correlation between RPR and myeloma prognosis has not been reported. Therefore, this study aims to explore the correlation between RPR level and the prognosis of multiple myeloma (MM) patients.

Methods: We retrospectively analyzed 145 newly diagnosed patients with MM. The receiver operating characteristic curve (ROC) method was used to determine the RPR cut-off value. In addition, we studied the correlation between pre-treatment RPR levels and clinical characteristics, immunophenotype, cytogenetics, and its impact on the disease prognosis.

Results: The optimal cut-off value for RPR was 0.12 and was divided into high RPR and low RPR groups. Patients in the high RPR group are more likely to have anemia, thrombocytopenia, high β2-macroglobulinemia, a high percentage of bone marrow plasma cells, late-stage status by Dury-Salmon (DS) and international staging system (ISS) (p < 0.05). More notably, between the high RPR and low RPR groups, the incidence rates of CD56-positive, D13S319-positive, RB1-positive, and 1q21 amplification were statistically significant (p < 0.05). Additionally, survival analysis revealed that compared with patients in the low RPR group, the median progression-free survival (PFS) and overall survival (OS) of patients in the high RPR group were substantially shortened (p < 0.05). Multivariate analysis confirmed that RPR ≥0.12, D13S319-positive, and 1q21 amplification were independent risk factors for poor PFS and OS.

Conclusions: RPR is a practical and effective prognostic marker in newly diagnosed patients with MM, and a high RPR is an independent poor prognostic factor.