Studying the Relation Between Fibromyalgia Severity and Neutrophil-to-Lymphocyte Ratio, Platelet-to-Lymphocyte Ratio, and Mean Platelet Volume

Background: Fibromyalgia is characterized by chronic widespread pain, which has been linked to neuroinflammation. Hematological indices, i.e., neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and mean platelet volume (MPV) have been shown to be effective markers in neurological diseases like depression. Aims: To study the association between fibromyalgia severity and the hematological indices (NLR, PLR, and MPV). Subjects and Methods: This was a hospital-based cross-sectional study of fibromyalgia patients satisfying the 2016 modification of the 2010/11 ACR criteria. Demographic and clinical characteristics were recorded along with fibromyalgia outcomes and hematological indices. Statistical analysis was done using descriptive statistics, ROC analysis using the Youden index, and Pearson and Spearman correlations. Results: A total of 266 patients were recruited. The (mean +/- S.D) NLR, MPV, and PLR were 1.92 +/- 1.26, 8.94 +/- 1.25, and 119.48 +/- 76.91, respectively. Patients with severe visual analog scale (VAS) pain scores had lower MPV (8.8 +/- 1.3) than those with mild/moderate pain (9.2 +/- 1.1, p = 0.016). MPV showed a mild negative correlation with the Fibromyalgia Impact Questionnaire-Revised (FIQR) score (R2 -0.31 p 0.004). MPV threshold of 8.95 was discriminated severely from mild/moderate VAS-pain score with a sensitivity of 52.3 % and specificity of 66.7%. Conclusions: MPV can possibly be considered as a biomarker for predicting pain severity in fibromyalgia. Given its inexpensive nature, MPV can be used as a cost-effective method to assess fibromyalgia severity in rural India.