Background/Objectives: Chronic kidney disease (CKD) progression is strongly influenced by systemic inflammation. The neutrophil-to-lymphocyte ratio (NLR), derived from routine blood counts, reflects the balance between innate and adaptive immunity and has been proposed as a marker of adverse renal outcomes. We hypothesized that elevated baseline NLR is associated with reduced kidney function and increased risk of progression to end-stage kidney disease (ESKD) in adults with non-dialysis CKD. Methods: Following PRISMA guidelines, we systematically searched MEDLINE, Embase, and Scopus for studies enrolling adults with CKD stages 1–4 that reported renal outcomes according to baseline NLR. The primary outcome was progression to ESKD or renal replacement therapy (RRT) initiation. Results: Six eligible studies were identified, of which four provided sufficient data for meta-analysis. Across cohorts, elevated baseline NLR was consistently associated with adverse renal outcomes. In pooled analyses, high NLR nearly doubled the risk of ESKD or RRT (RR 1.96, 95% CI 1.30–2.97). Leave-one-out sensitivity analysis strengthened the association while reducing heterogeneity. For kidney function, higher NLR was associated with lower baseline eGFR (SMD −1.59, 95% CI −2.38 to −0.80). Conclusions: Elevated NLR is a robust prognostic marker of renal function decline and progression to ESKD or RRT in non-dialysis CKD. As a simple and inexpensive biomarker, NLR offers additional predictive value beyond eGFR and albuminuria. Incorporating NLR into risk models may refine stratification, guide follow-up, and enable earlier therapeutic optimization. Prospective large studies are warranted to establish thresholds and validate its role in clinical practice.
Burlacu et al. (2025) studied this question.