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