Prognostic role of neutrophil–lymphocyte ratio in multiple myeloma: a dose–response meta-analysis

Background The neutrophil-lymphocyte ratio (NLR), a biomarker for systematic inflammation, has been recently identified as a prognostic factor for various types of both solid and hematologic malignancies. Our study presented here was the first meta-analysis assessing the prognostic role of NLR in multiple myeloma (MM). Methods We systematically searched PubMed, Embase, and ISI Web of Science for relevant studies. Odds ratios (ORs) or hazards ratios (HRs) with corresponding 95% CIs are pooled to estimate the association between NLR and clinicopathological parameters or survival of MM patients. Results Seven trials with 1,971 MM patients were enrolled in the meta-analysis, and the results indicated that elevated pretreatment NLR was significantly associated with advanced tumor stages (International Staging System [ISS] III vs ISS I-II: OR 2.427, 95% CI: 1.268-4.467; and Durie-Salmon III vs Durie-Salmon I-II: OR 1.738, 95% CI: 1.133-2.665). Moreover, increased NLR also predicted poorer overall survival (HR 2.084, 95% CI: 1.341-3.238) and progression-free survival (HR 1.029, 95% CI: 1.016-1.042). And two-stage dose-response meta-analysis revealed linear association between increased NLR and risk of mortality in MM patients. Conclusion We can conclude that MM patients with higher NLR are more likely to have poorer prognosis than those with lower NLR.