Association between neutrophil-to-lymphocyte ratio and the prognosis of patients with rheumatoid arthritis: a meta-analysis

Background: Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic systemic inflammation, posing a high risk of death, particularly from cardiovascular events. Finding simple and cost-effective prognostic biomarkers is crucial for risk stratification and improved patient management. The neutrophil-to-lymphocyte ratio (NLR), as a systemic inflammatory marker, has shown prognostic value in various diseases, but its comprehensive evidence in RA remains unclear. Methods: Following the PRISMA 2020 guidelines, relevant literature up to October 2025 was systematically searched in PubMed, Embase, Web of Science, and Cochrane databases. Observational studies were included. Random-effects models were used to pool odds ratios (OR) and 95% confidence intervals (CI). Robustness and publication bias were assessed using heterogeneity tests (I²), sensitivity analyses, and Egger's tests. Evidence quality was graded using the GRADE system. Results: Overall, seven studies were analyzed, and the meta-analytic findings indicated that elevated NLR was significantly correlated with all-cause mortality (OR = 1.70, 95%CI: 1.39-2.09, P<0.00001) and cardiovascular mortality (OR = 2.60, 95%CI: 1.61-4.21, P = 0.0001) in RA patients, and also with reduced disease remission rate (OR = 0.81, 95%CI: 0.68-0.96, P = 0.02). Heterogeneity for all outcomes was low (I²=0-16%), sensitivity analysis confirmed robustness, and publication bias was not statistically significant. GRADE assessment indicated low quality of evidence for all-cause mortality, moderate for cardiovascular mortality, and very low quality for remission rate. Conclusion: Analysis based on a multivariate adjusted model showed that high NLR is an important predictor of poor prognosis in RA patients. As an economical and readily available inflammatory marker, it holds promise for use in RA risk stratification and personalized treatment decision support, but further prospective studies are required to clarify the causal relationship and optimize the clinical cutoff value. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD420251234933.