Individual joints involvement pattern in psoriatic arthritis: A cross-sectional study in China.

Psoriatic arthritis (PsA) is characterized by multi-joint involvement, primarily affecting the small joints in the hands and feet. However, the specific pattern of joint involvement at an individual level remains uncertain. This study aimed to elucidate the pattern of joint involvement in a PsA cohort. Patients diagnosed with PsA were recruited for this cross-sectional study. Demographic, clinical, laboratory, personal and family history, and comorbidity data were collected. Descriptive statistical analysis was performed, and univariate and multivariate regression models were used to examine baseline factors influencing joint involvement. A total of 264 PsA patients (156 males) were included in the study. The results revealed a predominant involvement of peripheral facet joints. The second proximal interphalangeal joint (PIP) of the right hand exhibited the highest prevalence of swelling (18.9%), while the right knee joint had the highest prevalence of tenderness (24.2%). Older age and earlier onset of PsA were identified as independent factors associated with the swelling of the second PIP of the right hand. Older age, earlier onset of PsA, lower Psoriasis Area and Severity Index and higher Dermatology Life Quality Index scores were identified as independent factors associated with the tenderness of the right knee joint. In conclusion, the most commonly affected joints in PsA are the second PIP of the right hand and the right knee joint.