Value of Diverse Hematological Markers in Fibromyalgia: A Real-World Study

The aim of this study is to assess the diagnostic accuracy and potential role in reflecting systemic inflammation of a broad range of blood cell-derived indexes in fibromyalgia (FM). The efficacy of hematological markers, including the systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), and systemic inflammation aggregate index (AISI) in demonstrating systemic inflammation has not yet been investigated in FM.

Among the 2,829 patients assessed, a total of 502 patients and 90 age- and sex-matched individuals were involved in the study. Demographic characteristics, C-reactive protein, erythrocyte sedimentation rate, and hematological indexes [platelet-lymphocyte ratio (PLR), neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), SII, SIRI, and AISI] were calculated. Laboratory findings were compared between study groups. Receiver operating characteristic (ROC) analysis was utilized to assess their diagnostic potential.

Patients had significantly higher SII, SIRI, and AISI values than controls (p=0.011, p=0.004, and p<0.001, respectively). No significant differences existed in NLR, MLR, and PLR between groups. According to the ROC analysis, SII, SIRI, and AISI exhibited statistically significant accuracy in differentiating FM from controls (p=0.010, p=0.003, and p=0.002, respectively). However, the area under the curve values (95% confidence interval) of SII, SIRI, and AISI were 0.584 (0.543-0.624), 0.594 (0.553-0.634), and 0.618 (0.569-0.648), respectively.

SII, SIRI, and AISI values are higher in FM, reflecting a potentially increased inflammatory status. Yet, their diagnostic performance is below the acceptable level.