**1. Introduction**

Psoriatic arthritis (PsA) is a complex musculoskeletal disorder that has the clinical features of psoriasis, peripheral arthritis, spinal involvement, enthesitis, and dactylitis [1, 2]. Typically, skin lesions precede osteoarticular lesions [1–6], although osteoarticular lesions precede skin lesions in some cases. In these cases, the diagnosis is difficult and often results in a delay in treatment. Regardless, the appropriate management of PsA requires early diagnosis. Classification criteria of PsA (CASPAR criteria) consist of established inflammatory articular diseases with at least 3 points from the following features: current psoriasis (assigned a score of 2), a history of psoriasis (a score of 1), a family history of psoriasis (a score of 1), dactylitis (a score of 1), juxtaarticular new

bone formation (a score of 1), rheumatoid factor negativity (a score of 1), and nail dystrophy (a score of 1). The CASPAR criteria have been reported to be useful in assisting clinicians in the diagnosis of PsA because of high sensitivity and specificity than any other criteria [7].

PsA in many patients is associated with obesity, diabetes, hypertension, metabolic syndrome, fatty liver, and an increased risk of cardiovascular events compared to that of the general population [8]. In a realistic orthopedic outpatient clinical setting, little is unknown about the clinical features and the treatment status in patients with PsA. Whether PsA is associated with obesity or lifestyle-related diseases remains unknown.

We investigated the clinical characteristics of PsA, such as the onset pattern of PsA, the interval between the occurrence of skin lesions and osteoarticular lesions, and the distribution of arthritis such as peripheral and axial lesions and enthesitis. In addition, we examined whether obesity, hypertension, or diabetes mellitus was significantly increased in patients with PsA. We also examined the treatment status for PsA.
