Development of a new simplified comprehensive scoring system for polymyalgia rheumatica: Integration of PET/CT findings and clinical features.

OBJECTIVE

This study, based on previous single-center data, aimed to integrate [18F] Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) findings with the 2012 ACR/EULAR classification criteria for Polymyalgia rheumatica (PMR) to develop a new simplified comprehensive scoring system and further validate its diagnostic performance.

METHODS

We conducted a retrospective review of patients aged ≥50 years with musculoskeletal pain who underwent PET/CT examinations over the past decade. A total of 125 patients with PMR and 200 control subjects were included. The cohort was divided into a study cohort and a validation cohort. Based on PET/CT findings and clinical characteristics from the study cohort, we developed a new simplified comprehensive scoring system. The diagnostic performance of this new scoring system was further assessed in the validation cohort.

RESULTS

In the discovery cohort, the new scoring system, which combines PET/CT findings with clinical criteria, demonstrated a sensitivity of 92 % for diagnosing PMR, a specificity of 86.5 % in the overall control group, and a sensitivity of 90.4 % for distinguishing patients with rheumatoid arthritis (RA). The area under the receiver operating characteristic (ROC) curve (AUC) was 0.892 for the overall control group and 0.912 for the RA group. In the validation cohort, the new criteria achieved a sensitivity of 88 % and a specificity of 83.1 %.

CONCLUSIONS

The new simplified comprehensive scoring system integrates PET/CT findings with the 2012 ACR/EULAR clinical classification criteria, simplifying the scoring components to improve diagnostic performance and clinical utility, thus making it more accessible and practical for rheumatologists in clinical settings.