A Study on Early Screening and Disease Characteristics of Psoriatic Arthritis Based on PEST Questionnaire and Musculoskeletal Ultrasound

Background: Psoriatic arthritis (PsA) is a chronic inflammatory joint disease associated with psoriasis. Early diagnosis is crucial for preventing structural joint damage and improving long-term prognosis. Aim: This retrospective study applied the Psoriasis Epidemiology Screening Tool (PEST) combined with musculoskeletal ultrasound (MSUS) to identify early PsA and analyze differences in clinical and ultrasonographic features among patient subgroups. Methods: Psoriasis outpatients with a PEST score ≥ 1, who presented to the dermatology department between September 2022 and December 2023, were enrolled and underwent systematic MSUS examination covering 68 joints, 54 tendons, and 56 entheses. Based on MSUS findings and the Classification Criteria for Psoriatic Arthritis (CASPAR) criteria, patients were classified into high-risk PsA, subclinical PsA, and clinical PsA groups. Baseline characteristics, lesion distribution, and types were compared. Results: Among 178 included patients, 143 (80.34%) showed abnormal MSUS findings. The clinical PsA group had a significantly higher proportion of patients over 40 years compared to the high-risk PsA group ( P =0.002) and subclinical PsA group ( P < 0.001). Nail involvement was less frequent in the high-risk PsA group compared to the clinical PsA group ( P =0.026) and subclinical PsA group ( P =0.055). In patients with abnormal MSUS findings, the knees, metatarsophalangeal, and metacarpophalangeal joints were the most commonly affected sites. Hand proximal interphalangeal joint involvement was significantly more frequent in clinical PsA than in subclinical PsA ( P =0.035). Enthesitis, synovitis, and joint effusion were predominant in both subclinical PsA and clinical PsA groups, but synovitis ( P =0.008) was significantly more common in clinical PsA. Conclusion: Using a PEST score ≥ 1 as a screening threshold enables MSUS to effectively identify substantial subclinical and clinical lesions in psoriasis patients, thereby facilitating the early, broad detection of high-risk PsA individuals. Keywords: psoriatic arthritis, psoriasis epidemiology screening tool, musculoskeletal ultrasound, high-risk factors, sub-clinical PsA