Evaluation of the relationship between blood cell markers and inflammation, disease activity, and general health status in ankylosing spondylitis

OBJECTIVE: The aim of this study was to assess the relation of systemic immune inflammation index, systemic inflammation response index, and systemic inflammation aggregate index with disease activity, functional status, and general health status in ankylosing spondylitis. METHODS: Patients with ankylosing spondylitis and healthy volunteers were included in this cross-sectional study. Demographic data; disease activity measurements such as the Bath Ankylosing Spondylitis Disease Activity Index, the Ankylosing Spondylitis Disease Activity Score with C-reactive protein, and the Ankylosing Spondylitis Disease Activity Score with erythrocyte sedimentation rate; functional status such as the Bath Ankylosing Spondylitis Functional Index; and general health status such as the Assessment of Spondyloarthritis International Society Health Index of the patients were recorded. C-reactive protein, erythrocyte sedimentation rate, platelet to lymphocyte ratio, neutrophil to lymphocyte ratio, monocyte to lymphocyte ratio, systemic immune inflammation index, systemic inflammation response index, and systemic inflammation aggregate index values were recorded. Patients were grouped as active and remission according to the Bath Ankylosing Spondylitis Disease Activity Index score and as inactive-low and high-very high disease activity according to the Ankylosing Spondylitis Disease Activity Score. The correlation of laboratory parameters with disease-related parameters was tested. RESULTS: The indexes were significantly higher in patients compared to controls (p<0.001, for platelet to lymphocyte ratio p=0.03). No significant differences existed in any blood cell-derived indexes among patient groups categorized by disease activity (p<0.05 for all). Systemic immune inflammation index was weakly correlated with Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ρ=0.197 and p=0.049) and Ankylosing Spondylitis Disease Activity Score-erythrocyte sedimentation rate (ρ=0.201 and p=0.045). Systemic immune inflammation index was not correlated with Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, and Assessment of Spondyloarthritis International Society Health Index. No correlation was found between other indexes and disease-related variables. Platelet to lymphocyte ratio, systemic immune inflammation index, systemic inflammation response index, and systemic inflammation aggregate index showed a weak positive correlation with C-reactive protein and erythrocyte sedimentation rate (ρ=0.200–0.381). CONCLUSION: Systemic immune inflammation index, systemic inflammation response index, and systemic inflammation aggregate index can be used to indicate systemic inflammatory burden in ankylosing spondylitis patients. However, these indexes are not effective in indicating patients’ disease activity, general health status, and functional status.