Platelet to lymphocyte ratio and neutrophil to lymphocyte ratio in patients with rheumatoid arthritis

Objectives: It has been well documented that the platelet to lymphocyte ratio (PLR) and the neutrophil to lymphocyte ratio (NLR) are associated with outcomes for patients with gastric cancer, non-small cell lung cancer and acute heart failure. Inflammation may be the hidden factor that explains the correlation between NLP, PLR, and these diseases. However, to date, the data concerning NLR, PLR, and its association with inflammation are lacking in patients with rheumatoid arthritis (RA), thus, our aim to discuss whether NLR and PLR are associated with RA. Methods: Patients with RA and healthy individuals were included according to the determined criteria, and laboratory indicators were measured. Results: PLR and NLR were significantly higher in RA patients compared with healthy controls (3.20 +/- 2.06 vs. 1.56 +/- 0.47, P< 0.01; 192.85 +/- 101.78 vs. 103.49 +/- 28.68, P< 0.01). When leukocytes, neutrophil percentage, neutrophil, lymphocyte, platelet, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF) were considered as confounders (crude model), our results indicated that ESR and RF were correlated to RA. Of note, ESR, RF, and PLR were associated with RA after further adjustment based on crude model for PLR and NLR. Receiver operating characteristic (ROC) curves analysis showed that PLR values higher than > 115.7 evaluated RA with a sensitivity of 82.5%, a specificity of 74.8% and area under the curve (AUC) of 0.847. Conclusions: Our results suggest that PLR is associated with RA, and PLR may be an underlying indicator indicating the chronic subclinical inflammation in patients with RA.