The association of neutrophil-to-lymphocyte ratio with cardiovascular and all-cause mortality among the metabolic syndrome population

The neutrophil-to-lymphocyte ratio (NLR) has emerged as a novel inflammatory marker related to disease prognosis, this study aimed to evaluate the association between NLR and mortality in metabolic syndrome (MetS) patients.

This study used data from 13,156 participants with MetS, derived from the National Health and Nutrition Examination Survey from 1999 to 2020. The NLR was calculated, and its associations with cardiovascular disease (CVD) mortality and all-cause mortality were assessed by multivariate Cox regression, restricted cubic spline and Kaplan-Meier curves. The study performed subgroup analyses to validate the robustness of the findings in different populations. The predictive ability of NLR was evaluated using time-dependent receiver operating characteristic curve. The indirect impact of eGFR was explored by mediation analysis.

As NLR values increased, there was an obvious rise in the risk of mortality in MetS. The fully adjusted continuous model revealed a 16.0%, 14.4% elevated risk of CVD mortality (HR = 1.160; 95% CI: 1. 090-1.234, p < 0.0001) and all-cause mortality (HR = 1.144; 95% CI: 1. 086-1.206, p < 0.0001), respectively, with each one-unit increment in NLR. Comparing the highest to the lowest quartile of NLR, the top quartile exhibited a significantly increased risk of CVD mortality (HR = 2. 447; 95% CI: 1. 561-3. 836, p < 0.0001), and all-cause mortality (HR = 1. 53; 95% CI: 1. 188-1. 972, p = 0.001) among individuals with MetS. Subgroup analyses substantiated the stability of these associations in most populations. The curve under area for the 3, 5, and 10 years were 0.650, 0.716, and 0.645 for CVD mortality, and 0.746, 0.688, and 0.635 for all-cause mortality. Significantly, the eGFR acted as an intermediary in the relationship of NLR with CVD mortality and all-cause mortality, accounting for 9.85% and 9.86% of the effect, respectively.

The NLR served as a significant indicator for assessing the risk of mortality in the MetS population. Consequently, we recommended the regular assessment of NLR in MetS populations as a potentially advantageous method for evaluating their risk of mortality.