The 2023 ACR/EULAR Classification Criteria for Calcium Pyrophosphate Deposition Disease.

Area of Science:

• Rheumatology
• Crystal-induced arthritis

Background:

• Calcium pyrophosphate deposition (CPPD) disease is common but lacks validated classification criteria for symptomatic presentations.
• Diverse clinical manifestations of CPPD disease complicate diagnosis and research efforts.

Purpose of the Study:

• To develop and validate the first classification criteria for symptomatic calcium pyrophosphate deposition (CPPD) disease.
• To establish standardized criteria for identifying and classifying CPPD disease in clinical and research settings.

Main Methods:

• A multinational group followed established methodology, including item generation, patient profile evaluation, and multi-criterion decision analysis.
• Criteria were developed using a derivation cohort and validated in an independent cohort.
• Performance was assessed using sensitivity and specificity metrics.

Main Results:

• The 2023 ACR/EULAR criteria include specific findings (crowned dens syndrome, synovial fluid crystals) or a weighted score (>56 points) based on clinical, metabolic, laboratory, and imaging data.
• High sensitivity (92.2%–99.2%) and specificity (87.9%–92.5%) were achieved in both derivation and validation cohorts.
• The criteria effectively differentiate CPPD disease from its mimics.

Conclusions:

• The 2023 ACR/EULAR classification criteria for CPPD disease demonstrate excellent performance.
• These validated criteria are expected to significantly advance research and improve the classification of symptomatic CPPD disease.