NLR Shows Promise in Asthma Detection and Severity Stratification: Meta-Analysis

The researchers analyzed data from 19 studies, which included over 43,000 patients with asthma and more than 8,000 healthy controls. Using pooled statistical methods, they evaluated NLR values across different asthma severity groups and assessed how well NLR could distinguish asthma patients from healthy individuals through receiver operating characteristic (ROC) curve analysis.

The latest findings from this meta-analysis spotlighted the diagnostic utility of NLR. The results showed that NLR levels were significantly higher in individuals with asthma compared to healthy controls, with an area under the curve (AUC) of 0.92. Furthermore, NLR effectively differentiated between severe and non-severe asthma cases (AUC 0.91), making it a potentially useful tool for severity assessment. However, its ability to differentiate between moderate and severe asthma was limited, indicating the need for additional or complementary biomarkers to capture more nuanced stages of the disease.

The following were the key findings of the study:

• Individuals with asthma had significantly higher neutrophil-to-lymphocyte ratio (NLR) values compared to healthy controls.
• NLR levels increased progressively with worsening asthma severity.
• The meta-analysis showed a strong ability of NLR to differentiate asthma patients from healthy individuals (AUC = 0.929).
• NLR effectively distinguished severe asthma from non-severe cases (AUC = 0.914).
• Statistically significant differences in NLR were observed between mild and moderate asthma, and between severe and non-severe asthma.
• The ability of NLR to distinguish between moderate and severe asthma was limited.
• There were strongest NLR differences in pediatric populations.
• Studies conducted in developed countries reported greater variation in NLR levels.
• These findings suggest that demographic and regional factors may influence inflammatory responses in asthma.

Despite these promising insights, the study acknowledged key limitations. Considerable heterogeneity across the included studies may affect the consistency and broader applicability of the results. Additionally, since most studies were retrospective, they could be subject to selection and reporting biases. Moreover, while NLR shows strong potential, it may not sufficiently capture all aspects of disease progression on its own.

The authors concluded that the study supports the neutrophil-to-lymphocyte ratio (NLR) as an accessible and cost-effective biomarker for the identification and severity assessment of asthma. They highlighted the importance of conducting future prospective studies to validate these findings, establish standardized NLR cut-off values, and explore the potential of combining NLR with other clinical indicators to enhance the accuracy and precision of asthma management.

Reference:

Jin, L., Guo, J., Deng, K., & Yao, Y. (2025). Neutrophil-to-lymphocyte ratio as a biomarker for asthma identification and severity stratification: A systematic review and meta-analysis. Frontiers in Medicine, 12, 1620695. https://doi.org/10.3389/fmed.2025.1620695