Neutrophil-to-lymphocyte ratio is involved in the severity of ankylosing spondylitis

Ankylosing spondylitis (AS) is a progressive chronic inflammatory disease mainly characterized by axial skeleton and sacroiliac joint involvement. We aimed to investigate the relation between neutrophil-to-lymphocyte ratio (NLR) and disease severity of AS and to explore its availability in clinical practice.

A total of 102 AS patients and 60 individuals who were age- and gender-compatible with the control group were included into the study. Patients were divided into 2 groups according to Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores. Patients with BASDAI scores < 4 were considered to be having mild disease activity, whereas those with scores ≥ 4 were considered to be displaying severe disease activity. Hemogram test during the diagnosis, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) and other laboratory values of the control group were recorded.

NLR was observed to be higher in AS patients compared to the controls (2.47 ± 1.33 and 1.72 ± 0.47; respectively; p<0.0001). NLR was observed to be significantly higher in severe AS disease activity compared to the mild AS disease activity (2.72 ± 1.41, 2.20 ± 1.19; respectively; p = 0.001). NLR had statistical significant differences between mild disease activity compared to the controls (2.20 ± 1.19 and 1.72 ± 0.47, respectively; p = 0.263). There was a positive correlation between NLR and BASDAI (r = 0.193, p = 0.041). The performance of NLR evaluating the disease severity by Roc analysis had sensitivity of 69%, specificity of 54% (cut-off value 1.91), and AUC of 0.652 (95% Cl, 0.549-0.755) (p = 0.006).

NLR may be a simple and inexpensive marker to indicate disease activity in patients with AS in daily clinical practice (Tab. 3, Fig. 3, Ref. 25).