Background Psoriatic arthritis (PsA) is a complex chronic inflammatory disease associated with psoriasis that primarily affects peripheral joints. The impact of both skin and joint manifestations of PsA on disease burden is not well characterized.
Objectives To assess the relative contributions of skin and joint manifestations of PsA to the overall disease burden.
Methods This post-hoc analysis of the Adalimumab Effectiveness in Psoriatic Arthritis Trial (ADEPT) evaluated the subset of patients aged ≥18 years with active PsA (≥3 swollen joints and ≥3 tender joints) and an inadequate response to NSAID therapy with ≥3% body surface area [BSA] skin involvement of psoriasis. Joint damage (modified Total Sharp Score [mTSS]), physical function (Health Assessment Questionnaire disability index [HAQ-DI]), HRQoL (Short Form-36 [SF-36] and Dermatology Life Quality Index [DLQI]), pain, fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue [FACIT-F]), and physician's global assessment (PGA) were assessed at baseline and week 24. Multivariate linear regression was used to investigate associations of outcomes with skin and joint manifestations in patients with moderate (Psoriasis Area and Severity Index [PASI] ≤median, 6) or high (PASI >median, 6) skin involvement and low (DAS28 <3.2), moderate (DAS28 3.2–5.1) or high (DAS28 >5.1) joint involvement, with adjustment for age, sex, body weight, PsA duration, and methotrexate use.
Results 140 patients were included. At baseline, increasing skin involvement (high vs moderate after controlling for DAS28 value) was associated with worse SF-36 mental component summary score (MCS; difference = 4.2, P=0.0371), FACIT-F (difference = 5.0, P=0.0095), DLQI (difference = 4.5, P=0.0001), and PGA (difference = 6.5, P=0.0141). Greater joint involvement (high vs low and moderate vs low after controlling for PASI score) was associated with worse HAQ-DI (difference = 0.98, P<0.0001; 0.41, P=0.0097), SF-36 physical component summary score (PCS; difference = 16.0 and 9.9, both P<0.0001), pain (difference = 40.8 and 25.4, both P<0.0001), FACIT-F (difference = 12.8, P=0.0002; 4.6, P=0.1222), DLQI (difference = 5.0, P=0.0120; 1.3, P=0.4686), and PGA (difference=17.3, P=0.0003; 6.9, P=.0963). Among the 41 patients who achieved joint remission (DAS28 <2.6) at week 24, those who also achieved skin remission (PASI ≤3) experienced greater improvements in most outcomes vs those who did not (Table).
Conclusions Joint manifestations of PsA contributed to impaired physical function, physical health, pain, and fatigue. Skin manifestations contributed to decreased mental health, physical health, and fatigue. Despite achievement of joint remission, patients without skin remission experienced worse physical and functional impairments, pain, and physician-assessed outcomes. Management of PsA should aim to minimize both joint and skin involvement.
Acknowledgements Financial support for the study and medical writing support (Eric Bertelsen, Arbor Communications, Ann Arbor, MI) was provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the abstract. All authors contributed to the development of the publication and maintained control over the final content.
Disclosure of Interest P. Mease Grant/research support from: AbbVie, Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, Roche, UCB, Consultant for: AbbVie, Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, Roche, UCB, Speakers bureau: AbbVie, Amgen, BMS, Celgene, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, Roche, UCB, M. Mittal Shareholder of: AbbVie, Employee of: AbbVie, A. Joshi Shareholder of: AbbVie, Employee of: AbbVie, N. Chen Shareholder of: AbbVie, Employee of: AbbVie, J. Anderson Shareholder of: AbbVie, Employee of: AbbVie, Y. Bao Shareholder of: AbbVie, Employee of: AbbVie