Platelet/lymphocyte, neutrophil/lymphocyte, and lymphocyte/monocyte ratios as biomarkers for rheumatoid arthritis: correlation with disease activity

Abstract

Background

Assessment of disease activity in rheumatoid arthritis (RA) patients is essential for the adjustment of therapy. Inflammatory changes in lymphocytes, neutrophils, monocytes, and platelets supported the use of neutrophil/lymphocyte ratio (NLR), lymphocyte/monocyte ratio (LMR), and platelet/lymphocyte ratio (PLR) as markers of inflammation, we aimed to explore the clinical significance of PLR, NLR, and LMR in RA patients.

Results

The study included 120 RA patients and 50 healthy matched controls. Clinical and laboratory data of the patients were assessed. Disease activity was measured using disease activity score (DAS28). Complete blood count (CBC) with differential count was used for the calculation of NLR, PLR, and LMR. Patients had significantly high NLR, and PLR (p < 0.001) and significantly low LMR (p < 0.001) when compared with the control group. Also, there were significant differences in the three ratios between patients in activity and those in remission (p < 0.001). Similarly, there were significant differences in all three ratios between patients with different degrees of disease activity. DAS28 score was positively correlated with NLR, PLR (r = 0.666, p < 0.001, r = 0.586, p < 0.001) and negatively correlated with LMR (r = 0.761, p < 0.001). Receiver operating characteristic (ROC) curve analysis revealed that NLR had the highest sensitivity (86.9%) for RA disease activity, followed by PLR (85.9%) then LMR (76.2%), and regarding the specificity, NLR had high specificity (81%) followed by LMR (78%) then PLR (67%).

Conclusions

Given that NLR, PLR, and LMR were significantly different in patients when compared with the controls, also on comparing different degrees of disease activity and the three ratios were significantly correlated with DAS28 score, in addition to their good sensitivity and specificity for detection of RA disease activity, all this imply that they may be easy, reliable, cost-effective, and time-saving biomarkers when added to DAS28 score for the assessment of RA disease activity.