Association of Neutrophil to Lymphocyte Ratio with Patient Reported Outcomes in Knee Osteoarthritis

Background: Determining the association of neutrophil to lymphocyte ratio (NLR) and clinical disease severity in patients with mild and advanced stage knee osteoarthritis (OA).Method: We analyzed clinical scores and routine hematology panels of 111 subjects with symptomatic knee degeneration: mild OA (66) who underwent knee arthroscopy and advanced OA (45) who had total replacement. Results: Compared to the advanced OA group, the mild OA group was younger (54/67), had fewer females (1.75/5.43), and better scores: Euroqol EQ5D Index (0.50/0.25), VAS (visual analog scale) (65/44); International knee documentation committee subjective knee evaluation form—IKDC (31.6/20.24); Knee disability and osteoarthritis outcome score for joint replacement—KOOSJR (15.5/18.3); and better Kellgren–Lawrence stage (1.3/3.8). Patients with advanced disease had higher NLRs compared to mild OA group and controls: 2.82 versus 1.99 (p = 0.004) and 1.98 (p = 0.002). In the multiple regression model, NLR was only influenced by age (p < 0.001). In the subgroup analysis, for the early OA cases, NLR was significantly dependent to VAS (p = 0.006), IKDC (p = 0.001) and KOOSJR (p < 0.001). Conclusion: NLR was not associated with symptomatic knee OA, as determined by commonly used patient reported outcomes. However, for patients with mild degenerative modifications, EQ5D, VAS, and IKDC were independent predictors of NLR.