A Systematic Review and Meta-analysis of Clinical Studies on Ankylosing Spondylitis and Neutrophil to Lymphocyte Ratio.

BACKGROUND

Neutrophil to lymphocyte ratio (NLR) is a marker for many inflammatory diseases. Ankylosing spondylitis (AS) is among these inflammatory diseases, and many studies have compared the NLR ratio between patients with AS and healthy controls.

AIM

This study aims to systematically review and analyze the available evidence about the significance of NLR values in AS.

METHOD

Based on Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines, we searched Embase, Pubmed, ISI Web of Science, and Scopus databases from inception to August 2020 using ("Ankylosing spondyl* " OR "Bechterew Disease" OR "Rheumatoid Spondylitis") AND ((neutrophil* AND lymphocyte*) OR NLR) as key terms of the search strategy. Data selection and extraction were conducted separately by two authors. We appraised the included articles according to the Joanna Briggs checklist. Comprehensive Meta-analysis Version 2 was used for analysis and assessment of publication bias. I2 > 75% and p-value < 0.05 were considered significant.

RESULT

In total, 182 studies resulted from a search in all databases. Duplicate removal, title, abstract, and full-text screening yielded 12 related studies, with 11 included in the meta-analysis. Quality assessment was satisfying in all studies. Pooled difference in NLR means value between patients and controls was 0.38 (95% CI: 0.24-0.52, p-value <0.0001). An I2 of 51% and a Cochran Q test p-value of <0.05 indicated moderate heterogeneity; thus, subgroup analysis had no indication. Publication bias was not significant (Funnel plot with an Egger's intercept of -0.07; p-value=0.95).

CONCLUSION

Significant higher amounts of NLR may be strongly indicative of underlying inflammation in AS.