Calcium Pyrophosphate Deposition (CPPD) Disease

Inclusion Criteria - Acute forms of CPPD: retrospective part of the study

• Cases included in the COLCHICORT cohort (NCT03128905), for whom this was the first acute episode of CPPD

Inclusion Criteria - Chronical forms of CPPD : prospective part of the study

• Patients affiliated to the French social security system
• Age ≥ 65 years
• Diagnosis of chronic CPPD (recurrent acute or persistent arthritis), meeting ACR/EULAR 2023,11 classification criteria after evaluation by a rheumatologist in the rheumatology department
• Progression of CPPD rheumatism for at least 3 months and still active CPPD rheumatism, defined by a visual analogue scale (VAS) of disease activity ≥ 40 and/or presentation of at least 1 crisis over the last 3 months
• Glomerular Filtration Rate (GFR) in Chronic Kidney Disease Epidemiology (CKD EPI Collaboration) ≥ 30ml/min/1.73m2
• Minimum time between the last intake of a crisis treatment and inclusion in the study, depending on their half-life, in order to not interfere with the results of the omics analyses: 2 weeks (Nonsteroidal Anti-Inflammatory Drugs Per Os (PO) or Intramuscular (IM) or Intravenous (IV); corticosteroids PO or IV; colchicine PO; anakinra Subcutaneous (SC), 1 month (methotrexate PO, tocilizumab SC), 3 months (canakinumab SC, tocilizumab IV)
• Signed written consent for study participation

Exclusion Criteria - Acute forms of CPPD:

• Missing data concerning transcriptomic and metabolomic analyses.
• Opposition

Exclusion Criteria - For chronic forms of CPPD:

• History of gout or presence of monosodium urate (MSU) crystals on joint fluid,
• Cognitive decline (confusion and neurodegenerative diseases)
• Inability to provide informed consent and disease VAS
• Patient under guardianship or curatorship