Background Polymyalgia rheumatica (PMR) is an inflammatory rheumatic condition predominantly affecting older individuals, characterized by pain and stiffness in the shoulder and pelvic girdles. The PMR Activity Score (PMR-AS) is a composite tool for assessing disease activity, yet easily accessible inflammatory biomarkers that correlate with disease activity remain limited. The Systemic Immune-Inflammation Index (SII), derived from peripheral blood counts has emerged as a novel marker reflecting systemic inflammation. Objective To investigate the relationship between the SII index and disease activity as measured by the PMR-AS in patients diagnosed with PMR. Methods In this retrospective cross-sectional study, 180 patients diagnosed with PMR were included. Clinical and laboratory data at diagnosis were analyzed. PMR-AS was calculated at baseline. Pretreatment complete blood counts were used to determine the SII index. The association between SII index and PMR-AS was evaluated using Pearson correlation analysis. Patients were stratified into low disease activity and moderate-high disease activity groups based on a PMR-AS cut-off of 7. Multivariate linear regression was conducted to evaluate the independent association between SII index and PMR-AS. Results Among 180 patients with PMR, 86 (47.8%) had moderate-high disease activity. Coronary artery disease (CAD) was significantly more common in this group. Patients with moderate-high disease activity showed elevated WBC and neutrophil counts, reduced lymphocyte counts, and higher CRP levels. The SII index was markedly higher in the moderate-high disease activity group and demonstrated a moderate correlation with PMR-AS (r = 0.47). In multivariate analysis, CAD and SII index were independent predictors of moderate-high disease activity. ROC analysis confirmed that SII index demonstrated acceptable discriminatory performance moderate-high disease activity. Conclusion The SII index may reflect disease activity in PMR and could be considered a non-invasive, cost-effective adjunct to clinical evaluation.<Table Float="No" ID="Taba"> <tgroup cols="1"> <colspec align="left" colname="c1" colnum="1" /> <tbody> <row> <entry align="left" colname="c1"> Key Points • The SII index is a powerful predictor of disease activity in PMR. </entry> </row> <row> <entry align="left" colname="c1"> • Presence of CAD and higher SII index were independently associated with moderate-high disease activity, highlighting systemic inflammation. </entry> </row> <row> <entry align="left" colname="c1"> • Routine assessment of SII index may improve disease monitoring in PMR, supporting its integration into clinical evaluation alongside established disease activity scores. </entry> </row> </tbody> </tgroup> </Table>

Assessing disease activity in polymyalgia rheumatica using the systemic immune-inflammation index: A retrospective cross-sectional study

期刊论文
发表日期：

2026年3月14日

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Sibel Ösken,
Başak Bilir Kaya

摘要

Background

Polymyalgia rheumatica (PMR) is an inflammatory rheumatic condition predominantly affecting older individuals, characterized by pain and stiffness in the shoulder and pelvic girdles. The PMR Activity Score (PMR-AS) is a composite tool for assessing disease activity, yet easily accessible inflammatory biomarkers that correlate with disease activity remain limited. The Systemic Immune-Inflammation Index (SII), derived from peripheral blood counts has emerged as a novel marker reflecting systemic inflammation.

Objective

To investigate the relationship between the SII index and disease activity as measured by the PMR-AS in patients diagnosed with PMR.

Methods

In this retrospective cross-sectional study, 180 patients diagnosed with PMR were included. Clinical and laboratory data at diagnosis were analyzed. PMR-AS was calculated at baseline. Pretreatment complete blood counts were used to determine the SII index. The association between SII index and PMR-AS was evaluated using Pearson correlation analysis. Patients were stratified into low disease activity and moderate-high disease activity groups based on a PMR-AS cut-off of 7. Multivariate linear regression was conducted to evaluate the independent association between SII index and PMR-AS.

Results

Among 180 patients with PMR, 86 (47.8%) had moderate-high disease activity. Coronary artery disease (CAD) was significantly more common in this group. Patients with moderate-high disease activity showed elevated WBC and neutrophil counts, reduced lymphocyte counts, and higher CRP levels. The SII index was markedly higher in the moderate-high disease activity group and demonstrated a moderate correlation with PMR-AS (r = 0.47). In multivariate analysis, CAD and SII index were independent predictors of moderate-high disease activity. ROC analysis confirmed that SII index demonstrated acceptable discriminatory performance moderate-high disease activity.

Conclusion

The SII index may reflect disease activity in PMR and could be considered a non-invasive, cost-effective adjunct to clinical evaluation.

Key Points

• The SII index is a powerful predictor of disease activity in PMR.

• Presence of CAD and higher SII index were independently associated with moderate-high disease activity, highlighting systemic inflammation.

• Routine assessment of SII index may improve disease monitoring in PMR, supporting its integration into clinical evaluation alongside established disease activity scores.