Body surface area affected by psoriasis and the risk for psoriatic arthritis: a prospective population-based cohort study

Alexis Ogdie*, Daniel B. Shin, Þorvarður Jón Löve, Joel M. Gelfand

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Objective: Increasing psoriasis severity has been associated with comorbidities including cardiovascular disease. The objective of this study was to examine the association of psoriasis severity with the development of PsA. Methods: A prospective population-based cohort study was performed within The Health Improvement Network, a UK medical record database. Patients aged 25-60 years with a code for psoriasis were randomly selected between 2008 and 2011. Questionnaires were sent to their general practitioners to confirm the diagnosis of psoriasis and provide the patient's approximate body surface area (BSA). Incidence of PsA was calculated by BSA, and Cox proportional hazard ratios were used to examine the risk of developing PsA by BSA category after adjusting for other covariates. Results: Among 10 474 questionnaires sent, 9987 (95%) were returned, 9069 (91%) had confirmed psoriasis, and BSA was provided for 8881 patients: 52% had mild psoriasis, 36% moderate psoriasis and 12% severe psoriasis. The mean age was 46, and 49% were female. Mean follow-up time was 4.2 years (s.d. 2.1); the incidence of PsA was 5.4 cases per 1000 person-years. After adjusting for age and sex, BSA >10% [hazard ratio (HR) 2.01, 95% CI: 1.29, 3.13], BSA 3-10% (HR 1.44, 95% CI: 1.02, 2.03), obesity (HR 1.64, 95% CI: 1.19, 2.26) and depression (HR 1.68, 95% CI: 1.21, 2.33) were associated with incident PsA. Conclusions: In this large prospective cohort study, BSA assessed by general practitioners was a strong predictor of developing PsA, and obesity and depression were additive risk factors.

Original languageEnglish
Pages (from-to)1877-1884
Number of pages8
JournalRheumatology (United Kingdom)
Issue number5
Publication statusPublished - 5 May 2022

Bibliographical note

Publisher Copyright:
© 2021 The Author(s) 2021

© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email:

Other keywords

  • depression
  • epidemiology
  • obesity
  • psoriasis
  • psoriatic arthritis
  • Prospective Studies
  • Humans
  • Middle Aged
  • Risk Factors
  • Male
  • Incidence
  • Obesity/complications
  • Female
  • Body Surface Area
  • Psoriasis/complications
  • Arthritis, Psoriatic/complications
  • Cohort Studies


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