Correlation between the ultrasound 7 score and platelet-to-lymphocyte ratio as an inflammatory marker in patients with rheumatoid arthritis

Background/Aim: Accurate assessment of disease activity is essential in rheumatoid arthritis (RA). The aim of this study was to assess the relationship between the platelet-to-lymphocyte ratio (PLR), clinical disease activity and sonographic activity assessed using the ultrasound 7 (US7) score.Methods: This cross-sectional study included 105 patients with RA at Mansoura University Hospital. Patients were classified as having active RA (n = 53), sonographic remission (n = 22) or sonographic subclinical activity during clinical remission (n = 30). Clinical assessment, laboratory testing and musculoskeletal ultrasonography were performed. In this study, PLR was calculated by dividing the platelet count by the lymphocyte percentage.Results: US7 component scores were highest in active RA, intermediate in sonographic subclinical activity and lowest in sonographic remission. PLR was higher in active RA than in the other groups. No significant correlations were observed between PLR and US7 components within the studied groups. At a cut-off of 12.6, the reported sensitivity and specificity of PLR for detecting sonographic subclinical activity were 57 % and 98.8 %, respectively, with an area under the receiver operating characteristic curve of 0.77 (p = 0.001).Conclusion: PLR differed across disease activity groups, while ultrasonography identified residual inflammation in patients in clinical remission. The absence of significant within-group correlations between PLR and US7 components limits conclusions about PLR as a surrogate for sonographic activity. Further validation is required before the reported cut-off can be applied clinically.