PROGNOSTIC VALUE OF NEUTROPHIL-TO-LYMPHOCYTE RATIO IN CARDIOVASCULAR DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Cardiovascular diseases (CVDs) remain the leading cause of death globally. The neutrophil-to-lymphocyte ratio (NLR), an inexpensive inflammatory biomarker derived from routine blood counts, has shown promise for risk stratification, yet pooled prognostic evidence across heterogeneous CVD populations remains limited. This study systematically synthesised the prognostic value of baseline NLR for mortality across the full spectrum of CVD. Following PRISMA 2020 guidelines, PubMed, Scopus, and Web of Science were searched (January 2011–March 2026). Studies reporting multivariable-adjusted hazard ratios (HRs) for mortality in CVD patients with NLR as a prognostic exposure were included. Random-effects meta-analysis (DerSimonian–Laird), subgroup analyses (ACS vs. non-ACS; heart failure vs. CAD/interventional), leave-one-out sensitivity analysis, and publication bias tests (Egger’s, Begg’s) were performed. Twenty studies met the inclusion criteria; 16 contributed to the primary mortality HR pool. The pooled adjusted HR was 1.30 (95% CI: 1.20–1.40; p < 0.001; I² = 89.4%). The ACS/STEMI subgroup showed a higher pooled HR of 2.18 (95% CI: 1.15–4.13) compared with non-ACS conditions (HR = 1.30; 95% CI: 1.20–1.42). The association remained robust in all leave-one-out iterations. Egger’s test indicated potential publication bias (p = 0.031). Elevated NLR independently predicts mortality across diverse CVD populations. As a universally available, zero-cost biomarker, NLR holds considerable promise as an adjunctive risk-stratification tool. Future research should establish standardised cutoffs and test NLR-guided management strategies.