Clinical joints manifestations in patients with psoriatic arthritis on musculoskeletal ultrasound

To investigate the clinical joints manifestations under musculoskeletal ultrasound (MSUS) and hematological findings in patients with psoriatic arthritis (PsA), which may provide a basis for improving the early diagnosis of PsA.

From September 2016 to February 2021, 328 patients with psoriasis visited the dermatological and rheumatic outpatient of the Beijing Friendship Hospital were enrolled in this retrospective study. Patients were enrolled according to a paired-design method. The PsA group included 164 patients diagnosed with PsA, and the control group included 164 patients diagnosed with psoriasis without PsA. Both groups of patients were evaluated by a rheumatoid immunologist, a dermatologist, and a sonographer. Demographic data, course of disease, severity of skin lesions, combined diseases, and previous treatment were all collected. All patients received MSUS and blood examinations. Lower extremity enthsis diseases were evaluated by Glasgow ultrasound enthesitis scoring system (GUESS).

In the comparison of baseline clinical characteristics, the PsA group has longer course of psoriasis (P = 0.005), longer course of joints pain (P = 0.035), higher incidence of peripheral joints pain (P = 0.001), higher GUESS score (P < 0.001), and higher incidence of involved nails or toenails (P = 0.036) The most common joints involved were proximal interphalangeal joint (33.5%), knee (27.4%), and metacarpophalangeal joint (25.0%). Differences in clinical manifestations at different lower limb enthesitis on MSUS have also been proved. The positive incidences of rheumatoid factor (RF) (P = 0.002) and anti-cyclic citrullinated peptide (CCP) antibody (P < 0.001) in the PsA group were significantly higher than those in the control group. Binary Logistic regression showed that patients with anti-CCP antibody positive had a higher risk of active PsA compared to patients with negative antibodies in PsA group (OR: 0.626, 95%CI: 0.361-0.792, P < 0.05).

In conclusion, the most common joints involved were proximal interphalangeal joint, knee, and metacarpophalangeal joint in patients with PsA, and the common types of diseased joints manifestations on MSUS were synovial thickening, fluid accumulation, bone destruction, increased blood flow signals, and attachment site inflammation. GUESS scoring systems can be used to identify PsA in patients with psoriasis. Psoriasis patients with RF and anti-CCP antibody positive were more likely to develop PsA, and anti-CCP antibody positive was a risk factor for active PsA.

• GUESS scoring systems can be used to identify PsA in patients with psoriasis. • Psoriasis patients with RF and anti-CCP antibody positive were more likely to develop PsA, and anti-CCP antibody positive was a risk factor for active PsA.