Prognostic value of neutrophil-to-lymphocyte ratio among patients suffering from multiple myeloma: A systematic review and meta-analysis

Background Recent studies have considered the neutrophil-to-lymphocyte ratio (NLR) to be linked to the prognosis of individuals suffering from multiple myeloma (MM). Nevertheless, the existing research results remain controversial. Objectives To evaluate the prognostic value of NLR in MM using evidence-based medical methods. Design A Systematic Review and Meta-Analysis. Data Sources PubMed, Embase, Cochrane Library, and Web of Science (from inception to July 16, 2025). Methods PubMed, Embase, Cochrane Library, and Web of Science were systematically searched from database inception to July 16, 2025, for studies on the association between NLR and clinical outcomes. The main outcomes comprised progression-free survival (PFS) and overall survival (OS), estimated by hazard ratio (HR) and its 95% confidence interval (95% CI). The sensitivity analysis and the subgroup analyses were implemented to investigate the credibility of the results and the potential origins of the heterogeneity. Review Manager 5.4 and Stata 15.0 were adopted to perform all statistical analyses. Results Ten cohort studies (12 comparisons) involving 2,223 patients were included. The pooled data manifested a correlation between heightened NLR and shortened PFS (HR = 1.97, 95% CI: 1.20 – 3.22, p = 0.007) and OS (HR = 1.43, 95% CI: 1.11 - 1.84; p = 0.005). The subgroup analyses revealed that the association was particularly significant among patients aged ≥60 years, those with an NLR cutoff value >2, and those receiving chemotherapy alone (all P < 0.05). In some subgroups, such as the Asian region and baseline detection time, the association between NLR and OS was only marginally significant (P=0.07). However, this association did not reach statistical significance among patients receiving chemotherapy combined with autologous stem cell transplantation (ASCT), those aged <60 years, those with a cutoff value ≤2, or European patients. Moderate to high heterogeneity (I 2 > 50%) was still observed within some subgroups. Conclusion NLR serves as a readily accessible prognostic biomarker that may assist in risk stratification for patients with MM. Nonetheless, given the constraints of the included studies, more well-designed, high-quality, and multi-center research is warranted to further enrich the findings in this field.