Role of neutrophil to lymphocyte ratio in osteoarthritis: A systematic review and meta-analysis.

Background: Osteoarthritis (OA) involves low-grade inflammation. The neutrophil-to-lymphocyte ratio (NLR) may serve as a simple biomarker, but its role in OA remains unclear.

Aim: To review the existing scientific literature on the role of NLR in OA, a classic age-related disorder, to perform a meta-analysis of the available data.

Methods: The electronic databases PubMed, ProQuest, and Scopus were systematically searched from inception to March 1, 2024. The inclusion criteria were retrospective and prospective case-control studies involving human subjects with OA and healthy controls. The included studies needed to provide NLR levels for both OA patients and healthy controls and perform a comparative analysis of NLR levels between these groups.

Results: According to the PRISMA guidelines, fifteen articles were included in the meta-analysis after multiple screenings. The pooled results demonstrated a significant overall elevation of NLR in OA patients compared to healthy controls. (standardized mean difference = 0.39, 95% confidence interval: 0.03-0.75, P = 0.03). However, the subgroup analysis shows no significant differences in NLR levels when considering study design (retrospective vs prospective) and OA severity (severe vs mild-moderate). This suggests variability and potential limitations in using NLR as a consistent marker across different study types and OA severity.

Conclusion: Our study found that OA patients have higher NLR than healthy individuals. However, NLR did not significantly differ by study type or disease severity, suggesting its limited use in indicating OA severity.