title: Frequency of undiagnosed psoriatic arthritis among psoriasis patients in Australian dermatology practice.
abstract: BACKGROUND
  Psoriatic arthritis commonly develops in psoriasis patients and, if undiagnosed, can lead to potentially avoidable joint damage and an increased risk of comorbidity and mortality. Increased awareness of PsA symptoms among dermatologists provides an opportunity for earlier diagnosis, more timely therapy and prevention of disability.
  
  
  OBJECTIVE
  To provide Australian epidemiological data on the frequency of undiagnosed PsA among psoriasis patients in dermatology practice, and to investigate the impact of psoriasis on quality of life and work productivity.
  
  
  METHODS
  Nine tertiary centre dermatology practices enrolled patients presenting with plaque psoriasis and no prior rheumatologist-confirmed PsA diagnosis. Patients were screened using the Psoriatic Arthritis Screening and Evaluation (PASE) questionnaire and were referred to a rheumatologist for assessment of PsA status using CASPAR criteria if they had a PASE score ≥44.
  
  
  RESULTS
  Based on the composite and sequential application of PASE and CASPAR criteria, undiagnosed PsA among psoriasis patients in this study is 9% [95% CI: 6, 12]. The PPV of PASE in this setting is 26% [95% CI: 19, 34]. Nail involvement and chronic large plaque psoriasis were identified as independent positive predictors of PsA, whereas scalp psoriasis was an independent negative predictor of PsA. Patients with moderate-to-severe psoriasis (PASI ≥15) had lower quality of life scores than patients with less severe psoriasis.
  
  
  CONCLUSIONS
  In this study, the frequency of undiagnosed PsA in Australian dermatology practice was 9% among plaque psoriasis patients with no prior PsA diagnosis. Compared with psoriasis alone, the impact of undiagnosed PsA on health-related quality of life of psoriasis patients is substantial.
authors.affiliation: Specialist Connect, Woolloongabba, Qld, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Spelman
authors.affiliation: Eastern Health Clinical School, Monash University, Box Hill, Vic., Australia.
authors.forename: J C
authors.initials: JC
authors.lastname: Su
authors.affiliation: Dermatology, Westmead Hospital and Sydney Medical School, The University of Sydney, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Fernandez-Peñas
authors.affiliation: Royal Melbourne Hospital, Melbourne, Vic., Australia.
authors.forename: G A
authors.initials: GA
authors.lastname: Varigos
authors.affiliation: Royal North Shore Hospital, St Leonards, NSW, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Cooper
authors.affiliation: Deptartment of Dermatology, St Vincent's Hospital, Melbourne, Vic., Australia.
authors.forename: C S
authors.initials: CS
authors.lastname: Baker
authors.affiliation: Shire Australia Pty Ltd (formerly of Pfizer Australia Pty Ltd), Sydney, NSW, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Lee
authors.affiliation: HealthConsult (formerly of Optum, NSW, Australia), Sydney, NSW, Australia.
authors.forename: J M
authors.initials: JM
authors.lastname: Ring
authors.affiliation: Pfizer Australia Ltd.
authors.forename: K
authors.initials: K
authors.lastname: Thirunavukkarasu
mesh_terms: D000041:Absenteeism; D000328:Adult; D015535:Arthritis, Psoriatic / Q000175:diagnosis / Q000453:epidemiology*; D001315:Australia / Q000453:epidemiology; D003880:Dermatology / Q000706:statistics & numerical data; D004526:Efficiency; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009262:Nails; D000069597:Presenteeism; D015995:Prevalence; D011565:Psoriasis / Q000453:epidemiology / Q000473:pathology; D011788:Quality of Life; D012307:Risk Factors; D012536:Scalp Dermatoses / Q000453:epidemiology; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires