Predictive role of neutrophil-to-lymphocyte ratio in metabolic syndrome: Meta-analysis of 70,937 individuals

Neutrophil-to-lymphocyte ratio (NLR) has been shown to be an independent predictor for cardiovascular diseases and metabolic diseases. The role of NLR in metabolic syndrome (MS) has also been explored albeit with conflicting results. The objective of this study was to assess the predictive role of NLR in MS. We conducted a meta-analysis of observational studies to evaluate the predictive role of NLR in MS. Cochrane library, PubMed, Medline, Embase, and Scopus were systematically searched from their inception to December 2023. The Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines was followed. The statistical analysis was performed using RevMan 5.3 software. A randomeffect model was used. Twenty six studies enrolling 70,937 individuals were included in this meta-analysis. Compared with the individuals without MS, NLR value was significantly higher in the patients of MS (mean difference (MD) 0.40, 95% confidence intervals (CI): 0.27–0.52, P < 0.00001, I2 = 97%). The derived NLR value also was significantly higher in participants with MS than those without MS (MD 0.48, 95%CI: 0.13–0.84, P = 0.007, I2 = 96%). There was no statistically significant association for NLR between the patients with 4 metabolic risk factors (MRF) and those with 3 MRF, or between patients with 5 MRF and those with 4 MRF (MD 0.16, 95%CI: -0.02-0.35, P = 0.10, I2 = 84%; MD 0.12, 95%CI: -0.06-0.29, P = 0.20, I2 = 68%). However, MS patients with 5 MRF had a significantly higher mean NLR value than those with 3MRF (MD 0.37, 95%CI: 0.05–0.68, P = 0.02, I2 = 92%). Compared with the individuals with low NLR, incidence of MS was significantly higher in those with high NLR (OR 2.23, 95%CI: 1.25–3.98, P = 0.006, I2 = 97%). The findings of our meta-analysis suggested that the value of NLR and derived NLR were higher in MS patients. MS patients with 5 MRF had a significantly higher mean NLR value. High NLR also demonstrated a significantly increased the incidence of MS. NLR may be a good predictive biomarker in MS.