Clinical significance of the monocyte:lymphocyte ratio for ankylosing spondylitis patients with thoracolumbar kyphotic deformities

Purpose This study aimed to determine the clinical significance of the monocyte:lymphocyte ratio (MLR) in ankylosing spondylitis (AS) patients with thoracolumbar kyphotic deformity. Methods Ninety AS patients and 45 healthy controls were retrospectively enrolled. AS patients were divided into thoracolumbar kyphotic deformity (AS deformity) and spine normal (AS normal) groups. Blood parameters including C-reactive protein and erythrocyte sedimentation rate were determined. Receiver operating characteristic (ROC) curves and binary logistic regression analysis were conducted. Results Counts of white blood cells, neutrophils, and monocytes, and the neutrophil:lymphocyte ratio, platelet:lymphocyte ratio, and MLR were significantly higher in the AS than the control group. ROC curve results showed that the MLR yielded a higher area under the curve (AUC) value than other parameters, compared with controls. The MLR and monocyte count were higher in the AS deformity group than the AS normal group. ROC curve results indicated that the MLR yielded a higher AUC value than other parameters, compared with the AS normal group. Logistic regression suggested that the MLR was an independent predictor for thoracolumbar kyphotic deformity. Conclusions The MLR was elevated in AS patients, and was shown to be an independent predictor for thoracolumbar kyphotic deformity.