Co-occurrence of rheumatoid arthritis and calcium pyrophosphate deposition disease: A systematic literature review.
BACKGROUND: Rheumatoid arthritis (RA) and calcium pyrophosphate deposition (CPPD) disease are forms of inflammatory arthritis which may have similar presentations. There is growing recognition that these conditions can coexist, especially in elderly patients. This systematic literature review aims to examine the epidemiology and clinical characteristics of patients with both RA and CPPD disease. METHODS: A systematic literature search was performed from database inception to 31st January 2026 using the databases EMBASE, MEDLINE, Scopus, PubMed, CINAHL, and Cochrane. Keywords relating to RA, CPPD and chondrocalcinosis were used. Inclusion criteria were studies published in English and those that addressed the co-occurrence of RA and CPPD. RESULTS: The search yielded 24 studies comprising 12 cross-sectional studies, 2 case series, and 10 case reports published between 1965 and 2026. A total of 404 patients had both RA and CPPD, with 397/404 (98.3%) aged over 60 years old. Of 365 patients with serostatus data, 204/339 (60.2%) were seronegative for both rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA). Radiographic chondrocalcinosis was evident in 271/287 (94.4%). Of 271 patients with chondrocalcinosis, 162 (59.8%) were seronegative for both RF and ACPA. The most prescribed medications were methotrexate and prednisolone, in 75/205 (36.6%) and 64/205 (31.2%) patients, respectively. Colchicine was prescribed for 24/205 (11.7%). CONCLUSION: While the studies were small, RA, which is commonly seronegative, and CPPD can co-exist in the elderly. Higher-quality studies are required to determine the prevalence of co-existent RA and CPPD, thereby improving insight into the epidemiology and potentially enhancing outcomes of these patients.