Introduction:
This study aimed to investigate the relationship between the pan-immune-inflammation value (PIV), systemic immune-inflammation index (SII), and systemic inflammation response index (SIRI) and disease activity in rheumatoid arthritis (RA), characterized by chronic inflammation and immune system involvement, and to provide new insights into the clinical implications of RA.

Material and methods:
A total of 148 participants, including 97 RA patients (both newly diagnosed and established cases) and 51 healthy controls, were included in the study. Disease severity was assessed using the Disease Activity Score 28 (DAS28), and the relationship between DAS28 and PIV, SII, and SIRI, obtained from complete blood count results, was investigated. Additionally, C-reactive protein and erythrocyte sedimentation rate measurements were included in the study.

Results:
The average age of RA patients was significantly higher than that of healthy individuals (p = 0.002). A positive correlation was found between the DAS28 score and the inflammation indices (SII, PIV, SIRI), with 65.98% of RA patients in the active phase and 34.02% in remission. Systemic immune-inflammation index had a predictive accuracy of 75.26%, PIV 71.13%, and SIRI 72.16%. The AUC (area under curve) values for SII, PIV, and SIRI were 0.717, 0.719, and 0.717, respectively, with cutoff values of 611.45, 323.88, and 1.18. Sensitivity and specificity were calculated as 57.81% and 60.61% for SII, 60.94% and 63.64% for PIV, and 59.38% and 63.64% for SIRI.

Conclusions:
The findings revealed that PIV, SII, and SIRI were elevated in individuals with RA and may serve as complementary diagnostic markers. PIV, SII, and SIRI, as measures of disease activity in RA, may help monitor treatment efficacy and improve patient prognosis.