Biomarkers of Psoriatic Arthritis Phenotypes

  • Deepak Jadon

Student thesis: Doctoral ThesisPhD


Background: Psoriatic arthritis (PsA) is a chronic heterogenous inflammatory arthritis with five phenotypes. The two least studied phenotypes are investigated in this thesis, including: psoriatic spondyloarthropathy (PsSpA) and psoriatic arthritis mutilans (PAM). The aims of this thesis were to determine the prevalence, clinical characteristics and radiographic characteristics of PsSpA and PAM in a cohort of PsA patients, and serum-soluble bone- turnover biomarkers of these phenotypes. Aims: Comparisons were made with PsA patients without axial disease (pPsA), and ankylosing spondylitis (AS) patients.Methods: A prospective single-centre cross-sectional study was conducted of PsA and AS patients. Serum on psoriasis-only patients (PsC) and healthy controls (HC) were also obtained. Multivariate clinical, radiographic, genetic and serum biomarker comparisons were made between these five groups of subjects.Results: The study enrolled 201 PsA and 201 AS patients, who were then reclassified as 118 PsSpA, 127 pPsA and 157 AS cases, alongside 200 PsC and 50 HC subjects. Several clinical biomarkers, imaging biomarkers, serum-soluble biomarkers and genetic biomarkers were identified that differentiate PsSpA from pPsA and AS. PsSpA affected a significant proportion of PsA patients, and was not a milder version of AS. PsSpA involvement was as disabling and clinically impactful as AS. PAM was found to be associated with PsSpA, and clinical biomarkers of PAM occurrence and radiographic progression were identified.Conclusions: In conclusion, this thesis indicates that PsSpA is on a spectrum of musculoskeletal disease, in between pPsA and AS; with PsSpA comprising a continuum itself, and with a phenotype expression related to disease duration. These findings may prompt the inception of an international-consensus classification system for PsSpA, for which there is a great clinical need. Given that PsSpA has its own discrete clinical and biomarker signature, its clinical management and research should be tailored from that of pPsA and AS. Ultimately this may further the effort for stratified and personalised medicine.
Date of Award26 Jan 2016
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorNeil McHugh (Supervisor), Alison Nightingale (Supervisor), Raj Sengupta (Supervisor) & Mark Lindsay (Supervisor)


  • Biomarkers
  • phenotypes
  • ankylosing spondylitis
  • Psoriasis
  • radiographs

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