RT Journal Article SR Electronic T1 Oligoarticular Versus Polyarticular Psoriatic Arthritis: A Longitudinal Study Showing Similar Characteristics JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP jrheum.210434 DO 10.3899/jrheum.210434 A1 Dafna D. Gladman A1 Justine Y. Ye A1 Vinod Chandran A1 Ker-Ai Lee A1 Richard J. Cook YR 2021 UL http://www.jrheum.org/content/early/2021/07/25/jrheum.210434.abstract AB Objective The objectives of this study were to determine whether patients with oligoarticular presentation differ from those with polyarticular presentation and identify potential predictors for evolution of oligoarthritis to polyarthritis in patients with PsA. Methods Patients who entered the University of Toronto PsA clinic between 1978 and 2018 within 12 months of diagnosis were identified. Only patients with ≥ 2 clinic visits were included. Patients were followed at 6 to 12-month intervals according to standard protocol, which included demographics, clinical history, detailed clinical examination, laboratory information and patient questionnaires. Radiographs were done at 2-year intervals. Oligoarthritis was defined by the presence of ≤4 inflamed joints and progression as an increase to ≥5 joints. Statistical analyses included logistic regression models as well as Weibull regression models adjusted for age, disease duration and sex. Results 192 of 407 (47%) patients presented with oligoarthritis. While demographic features were similar to those with polyarthritis, more patients with polyarthritis presented with dactylitis and enthesitis. Similar joint distribution was observed, with small joints of the hands and feet being most commonly affected. Patients with polyarthritis had higher HAQ and lower SF-36 scores. 117 of 192 oligoarticular patients (61%) remained oligoarticular and 75 (39%) progressed to polyarthritis. Lower SF-36 mental component summary score was the predictor for progressing to polyarthritis. Conclusion Oligoarticular PsA occurs in 39% of patients with PsA and is similar to polyarticular disease, with most patients having small joint involvement. The only predictor for progression to polyarthritis was a lower SF-36 mental health component.