EXPRESS: The Novel Log10 (Lymphocyte/MID%) Ratio Outperforms CRP and Traditional Inflammatory Indices as a Diagnostic Biomarker for Metabolic Syndrome in Postmenopausal Women

BACKGROUND: Postmenopausal metabolic syndrome (MetS) arises from the complex interplay between estrogen deficiency and systemic inflammation. Yet, standard risk indicators, including C-reactive protein (CRP) and traditional hematological indices (NLR, LMR, NMR), are often limited by low specificity, inconsistent reliability, or high cost. PURPOSE: This study validated the diagnostic precision of a novel hematological metric, the log10(Lymphocyte/MID%) ratio, benchmarking it against standard indices and the novel biomarkers Subfatin and Interleukin-40. STUDY TYPE: A comparative cross-sectional study. POPULATION: 80 postmenopausal women aged 50 years or older were recruited and categorized into MetS (n=43) and non-MetS (n=37) cohorts according to NCEP ATP III guidelines. Assessment Technique(s) or Outcome(s): Fasting blood samples were analyzed for complete blood count (CBC) to calculate the novel log10(Lymphocyte/MID%) index. Serum Subfatin and IL-40 concentrations were quantified via ELISA alongside routine biochemical profiling. STATISTICAL TESTS: Receiver Operating Characteristic (ROC) curve analysis was used to evaluate diagnostic accuracy and optimal cutoffs. Multivariable binary logistic regression was applied to assess independent predictive value after adjusting for covariates. RESULTS: The MetS cohort exhibited a significant elevation in the log10(Lymphocyte/MID%) ratio (Median 1.63 vs 1.50, p < 0.001). The proposed index yielded the highest diagnostic accuracy (AUC=0.746), surpassing CRP (AUC=0.625), LMR (AUC=0.654), and NLR (AUC=0.465). With a cutoff set at >1.61, specificity reached 86.5%, representing a significant improvement in excluding false positives compared to conventional indices. Even after correcting for age, BMI, and medications via multivariable logistic regression, the ratio remained a significant independent predictor (adjusted OR=1.71 per 0.1-unit increment; p=0.013). Conversely, no statistical separation was observed for Subfatin (p=0.398) or IL-40 (p=0.692). DATA CONCLUSION: We identify the log10(Lymphocyte/MID%) ratio as a promising, independent marker for postmenopausal metabolic dysregulation, demonstrating moderate diagnostic discrimination, and offering a highly specific, low-cost tool for early risk stratification. Further validation in larger cohorts is recommended.