Clinical Characteristics of Psoriatic Arthritis in Chinese Patients: A Cross-Sectional Study

Introduction The clinical features of psoriatic arthritis (PsA) varied in different studies from different countries, nevertheless rarely reported from China. We aimed to show the portraits of Chinese PsA patients. Methods Demographics as well as clinical and laboratory data at the first visit of a PsA cohort were collected. Joints and entheses were further assessed by imaging techniques. The correlation between psoriasis severity index (PASI) and disease activity in PsA (DAPSA) was analyzed. The metabolic comorbidities were also explored among patients with different disease activity. Results Three hundred patients with definite PsA were enrolled in this study; 159 (53.0%) of them were male. Their median age was 39 (31, 51) years with disease duration of 3 (0.6, 7) years; 15.6% patients were HLA-B27-positive, and 37.8% patients reported a family history of psoriasis or PsA. Among 300 patients, psoriasis presented earlier than arthritis in most of them (214, 74.0%), while 48 (16.6%) patients presented with arthritis before psoriasis. Articular involvement was found in 293 (97.7%) patients. Polyarticular type was most common, with proximal interphalangeal as most frequently involved joints. Axial joint involvement was found in 45 (15.4%) patients. Dactylitis was observed in 94 (31.3%) patients, most often at the second, third, and fourth toes. Enthesitis was found in 18 (6.0%) patients by physical examination, however in 129/227 (56.8%) patients by ultrasound. The DAPSA score was correlated with PASI (r = 0.22, p = 0.021). A variety of comorbidities were more often observed in patients with moderate/high disease activity comparing with those in remission/low-disease activity, especially type 2 diabetes with statistically significant difference (19.1 vs. 4.1%, p = 0.023). However, further logistic regression analysis showed diabetes was not independently associated with moderate/high disease activity. The most frequently prescribed medication was methotrexate (101, 66.4%). Biological agents were applied in 25 (16.4%) patients. Conclusions Polyarticular involvement was most common in Chinese PsA patients. Ultrasound dramatically increased the identification of peripheral enthesitis. Active PsA patients were more likely to have comorbidities.