Background:Calcium pyrophosphate deposition disease (CPPD), also known as pseudogout, is a prominent member of the crystal deposition diseases much like gout where urate crystals are the pathogens. CPPD is differentiated from chondrocalcinosis, a radiographic finding showing joint calcification, which may or may not be relevant for the clinical picture of patients (1).Objectives:To determine the prevalence of chondrocalcinosis in different inflammatory rheumatic diseases.Methods:In a retrospective cross-sectional study design we reviewed the records of not established new patients presenting to our center between 1.1.2016 and 31.12.2018. Based on the availability of radiographs of hands and feet, 514 patients were identified including 181 patients with CPPD, 273 with rheumatoid arthritis (RA), 143 seropositive (52.4%) and 130 seronegative, 30 with gout and 30 with polymyalgia rheumatica (PMR). Radiographs of hands and feet were available from all patients, of the knee in 376 cases. All images were read by two experienced readers with no access to clinical data.Results:Almost all patients had a short disease duration of < 1 year. In patients diagnosed with CPPD all radiographs showed chondrocalcinosis (93%) at some location, mostly in the hands. This was different in seronegative (36.5%) and seropositive (30.3%) RA. Chondrocalcinosis was found less frequently also in gout (18.8%) and PMR (12.5%). More data are shown in the Table 1. Radiographic chondrocalcinosis was present in more than one joint in 36.6% patients with CPPD, in 11.9% in seropositive and in 17.3% in seronegative RA. Patients with CPPD were older and had acute attacks more often than RA patients. While RA patients were more frequently on methotrexate (MTX), patients with CPPD were more often on colchicine.Table 1.Radiographic and clinical features of the examined patientsConclusion:There were a lot of similarities but also some important differences between patients with CPPD and RA with no major differences between seropositive and seronegative RA. Of interest, radiographic chondrocalcinosis was seen in more than a third of RA patients. Importantly, clinical symmetry of arthritis and involvement of hands did not differentiate between CPPD and RA, mainly the acuteness of attacks did. Co-occurrence of both diseases was frequently observed. There was no major difference between seropositive and seronegative RA.References:[1]Rosenthal AM, Ryan LM. N Engl J Med. 2016Disclosure of Interests:None declared.
Calcium Pyrophosphate Deposition Disease and Associated Medical Comorbidities: A National Cross-Sectional Study of US Veterans