Overlap of Gout and Calcium Pyrophosphate Deposition with Osteoarthritis, Rheumatoid Arthritis, and Psoriatic Arthritis: Epidemiology, Clinical-Radiological Profiles, Outcomes, and Management

The crystal arthropathies gout and calcium pyrophosphate deposition (CPPD) disease represent a significant subset of rheumatic and musculoskeletal diseases, yet their overlap with common entities such as osteoarthritis (OA), rheumatoid arthritis (RA), and psoriatic arthritis (PsA) remains underrecognized. We conducted a structured narrative review of studies published through August 2025, exploring the epidemiology, clinical presentation, imaging characteristics, and treatment implications of these overlapping conditions. We particularly examine how crystal deposition may mimic or complicate the clinical course of OA, RA, and PsA, especially in older adults with multimorbidity. Recognizing these overlaps is critical to avoid misdiagnosis, inappropriate escalation of immunomodulatory therapy, and missed opportunities for targeted crystal-directed treatment.