PO:07:107 | Performance of the 2010 ACR/EULAR classification criteria for Rheumatoid Arthritis in a group of elderly onset patients

Alessandra Rai¹, Pierluigi Macchioni¹, Giovanni Barausse², Luigi Boiardi¹, Giuseppe Paolazzi², Carlo Salvarani¹, Andreina Manfredi¹ | ¹University of Modena and Reggio Emilia, USL-IRCCS Reggio Emilia, Italy; ²Rheumatology Unit, Ospedale di Trento, Italy

Background. Differentiating elderly-onset rheumatoid arthritis (EORA) from polymyalgia rheumatica (PMR) is challenging in a substantial proportion of patients, largely due to the lack of disease-specific serum biomarkers and the frequent overlap in clinical presentations. This diagnostic complexity is particularly evident in cases where EORA presents with a PMR-like onset, in seronegative EORA, and in PMR patients who develop peripheral synovitis—subgroups in which traditional clinical and laboratory criteria often fail to provide a definitive distinction Objective: Aim of this study was to compare the performance of the 2010 ACR/EULAR classification criteria for rheumatoid arthritis (RA) and polymyalgia rheumatica (PMR) in a consecutive cohort of elderly patients presenting with new-onset arthritis, with the aim of facilitating early diagnosis of RA.

Methods. All patients with early arthritis seen at our two centres were followed according to a standardized protocol which included clinical examination (including 66 joint count), determination of laboratory parameters, X-ray examination of hands and feet. At baseline classification criteria for RA and PMR were used for each patient, patients entered the study if diagnosis of RA or PMR was confirmed according to rheumatologist’s expert opinion after an observation of at least 12 months. Diagnostic performance of ACR/EULAR 2010 classification criteria were evaluated and compared in the two groups of patients.

Results. Consecutive patients with new diagnosis of EORA or PMR patients entered the study. Table 1 compare demographic, clinical and laboratory data between the two populations. Four groups were identified at baseline: 21 patients satisfied both classification criteria (group 1), 48 didn’t satisfied any classification criteria (group 2), 82 patients satisfied classification criteria for RA (group 3) and 135 those for PMR (group 4). Follow-up data of at least 12 months were available for 268 patients: in patients from group 3 diagnosis of RA was confirmed in 80/82 cases and among patients of group 4, diagnosis of PMR was confirmed in 119/135 patients. Among not classifiable patients (considered as the total of group 1 and group 2), RA was diagnosed in 49/69 patients (of which only 11% % were seropositive RA) while PMR was diagnosed in 20/69 patients, at follow-up.