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Updated: Apr 10, 2026

Author Spotlight: Self-Assessment Protocol for Predicting Psoriatic Arthritis in Psoriasis Patients
Published on: March 1, 2024
Prevalence and Clinical Characteristics of Psoriatic Arthritis in Japan
Yuri Ohara1, Mitsumasa Kishimoto2, Naoho Takizawa1
1From the Immuno-Rheumatology Center, and the Department of Dermatology, St. Luke's International Hospital, Tokyo; Department of Rheumatology, and the Department of Dermatology, Kameda Medical Center, Chiba, Japan; Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts; Allergy, Immunology, and Rheumatology Division, University of Rochester Medical Center, Rochester, New York, USA; Department of Dermatology, Nissay Hospital; Department of Orthopedics, National Hospital Organization, Osaka Minami Medical Center, Osaka, Japan.Y. Ohara, MD*, M. Kishimoto, MD*, Immuno-Rheumatology Center, St. Luke's International Hospital; N. Takizawa, MD, Department of Rheumatology, Kameda Medical Center; K. Yoshida, MD, MPH, Department of Epidemiology, Harvard School of Public Health; M. Okada, MD, Immuno-Rheumatology Center, St. Luke's International Hospital; H. Eto, MD, Department of Dermatology, St. Luke's International Hospital; G.A. Deshpande, MD, MA, Immuno-Rheumatology Center, St. Luke's International Hospital; C.T. Ritchlin, MD, Allergy, Immunology, and Rheumatology Division, University of Rochester Medical Center; A. Tanaka, MD, Department of Dermatology, Kameda Medical Center; M. Higashiyama, MD, Department of Dermatology, Nissay Hospital; K. Matsui, MD, Department of Rheumatology, Kameda Medical Center; S. Tsuji, MD, Department of Orthopedics, National Hospital Organization, Osaka Minami Medical Center.
Objective:
To investigate the prevalence of psoriatic arthritis (PsA) in Japanese patients with psoriasis.
Methods:
A multicenter, noninterventional, retrospective cross-sectional study was conducted at 3 tertiary care centers in Japan. PsA was diagnosed by rheumatologists based on clinical findings. Prevalence of PsA, clinical characteristics, comorbidities, and treatment patterns were examined.
Results:
PsA was identified in 431 of 3021 patients with psoriasis, with a mean prevalence of 14.3% (range, 8.8-20.4%). No large differences between these results and previous reports from Western countries were observed in arthritis distribution, skin disease type, or treatment selection.
Conclusion:
The prevalence of PsA in patients with psoriasis in Japan approaches 20% in some areas, similar to that observed in Western countries, and is higher than previously reported in Asia. Clinical features including age, sex, age at onset, and manifestation patterns were also similar to those reported in the West.
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