Prognostic value of the neutrophil-to-lymphocyte ratio in POEMS syndrome

POEMS syndrome is a rare paraneoplastic disorder driven by clonal plasma cell proliferation and systemic inflammation, but existing prognostic models inadequately incorporate inflammation-related parameters. The neutrophil-to-lymphocyte ratio (NLR)-a simple, accessible marker of systemic inflammation and immune status-lacks systematic prognostic validation in POEMS syndrome. This single-center retrospective study enrolled 61 patients. The cohort was stratified into two eras (2010-2017 and 2018-2025) to assess temporal consistency. Receiver operating characteristic analysis was used to derive an exploratory NLR cut-off for overall survival. Kaplan-Meier curves and Cox proportional hazards regression were used to assess associations between NLR and progression-free survival (PFS), overall survival (OS), and independent prognostic significance. The effect modification by Li's prognostic risk strata was explored using interaction and stratified analyses. Correlations were tested by Spearman's coefficient between NLR and C-reactive protein (CRP), and AUCs were compared by DeLong's test. ROC analysis showed moderate discrimination of baseline NLR for OS (AUC 0.736, 95% CI 0.613-0.860; P = 0.006), and the exploratory cut-off was 2.773. Patients with NLR > 2.773 had significantly shorter PFS (median 62 months vs not reached; P < 0.001) and OS (median 76 months vs not reached; P < 0.001) than those with NLR ≤ 2.773. Multivariable Cox regression confirmed NLR > 2.773 as an independent prognostic factor for inferior PFS (HR 3.547, 95% CI 1.086-11.586; P = 0.036). In Li's high-risk subgroup, high NLR further separated survival curves, although the formal interaction for PFS was not significant (P for interaction = 0.270), and OS interaction modeling was limited by few death events. CRP showed prognostic relevance, NLR correlated moderately with CRP (Spearman's ρ = 0.49, P < 0.001). A combined NLR + CRP model did not significantly improve OS discrimination over either marker alone (DeLong tests, all P > 0.05). Collectively, elevated baseline NLR is associated with inferior PFS and OS in POEMS syndrome and may reflect an inflammation-related risk phenotype. As a simple and widely available index, NLR may complement existing prognostic frameworks by incorporating an inflammation-immune dimension. External validation in independent multi-center cohorts is warranted.