Evaluation of Inflammatory Scores as Diagnostic Markers for Polymyalgia Rheumatica

Area of Science:

• Rheumatology
• Clinical Immunology
• Diagnostic Biomarkers

Background:

• Polymyalgia rheumatica (PMR) is a common inflammatory condition in older adults.
• PMR diagnosis is challenging due to overlapping symptoms with other diseases.
• Novel diagnostic markers are needed to improve PMR identification.

Purpose of the Study:

• To evaluate the diagnostic utility of four laboratory-based inflammatory scores for PMR.
• To compare the diagnostic performance of systemic immune-inflammation index (SII), C-reactive protein-to-albumin ratio (CAR), albumin-to-globulin ratio (AGR), and prognostic nutritional index (PNI) in differentiating PMR from rheumatoid arthritis (RA).
• To explore the association between these scores and clinical manifestations of PMR.

Main Methods:

• Retrospective analysis of 156 PMR and 408 RA patients' medical records (2001-2021).
• Evaluation of diagnostic performance using receiver operating characteristic (ROC) curve analysis.
• Logistic regression analysis to assess score effectiveness.

Main Results:

• PMR patients showed higher SII and CAR, and lower AGR and PNI compared to RA patients.
• CAR exhibited the highest diagnostic performance (AUC 0.823), followed by SII (AUC 0.797).
• Combined scores yielded an AUC of approximately 0.835, enhancing diagnostic ability. Elevated SII/CAR and decreased AGR/PNI correlated with specific clinical and laboratory findings.

Conclusions:

• Serological inflammatory scores (SII, CAR, AGR, PNI) are valuable diagnostic markers for PMR.
• The combination of these scores significantly improves diagnostic accuracy.
• These markers aid in distinguishing PMR and understanding its clinical associations.