Objective To compare the characteristics of patients with psoriatic arthritis among patient groups stratified by degree of skin and joint involvement, and to evaluate the relationship between skin severity and joint activity.
Methods Body surface area (BSA) and Clinical Disease Activity Index (CDAI) at enrolment were analysed. Patient characteristics were stratified by skin severity and joint activity. Baseline patient characteristics, clinical and disease characteristics and patient-reported outcomes were compared. The strength of the relationship of skin severity and joint activity was evaluated using methods for categorical variables (χ2 test, Cramer’s V) and continuous variables (linear regression).
Results 1542 adult patients in the Corrona Psoriatic Arthritis/Spondyloarthritis Registry enrolled between 21 May 2013 and 20 September 2016 were analysed. Most patients in the BSA >3%/CDAI moderate/high subgroup had worse clinical and patient-reported outcomes. A significant (p<0.001) modest association (Cramer’s V=0.1639) between skin severity and joint activity was observed among all patients at enrolment. Patients with higher skin severity were two times more likely to have higher joint involvement (OR 2.27, 95% CI 1.71 to 3.01). A significant linear relationship between CDAI and BSA was observed. Effect modification showed this linear relationship was modified by age, gender, insurance, work status, current therapy, Health Assessment Questionnaire, Nail visual analogue scale, minimal disease activity, dactylitis count, patient-reported pain and fatigue.
Conclusion Skin severity is modestly correlated with joint activity, and patients with higher skin severity are two times more likely to have increased joint involvement. Clinicians need to address both skin severity and joint activity in treatment decisions.
- psoriatic arthritis
- outcomes research
- disease activity
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Presented at Portions of this work have been previously presented at the 2017 ACR/ARHP Annual Meeting, 3–8 November 2017, San Diego, California, Poster No 62600, 'The relationship between the degree of skin involvement and joint activity in patients with PsA: experience from the Corrona Registry.'
Contributors All authors have made substantial contributions to the intellectual content of the manuscript: conception of the work; design of the work; acquisition of data for the work; analysis of data for the work; interpretation of data for the work; drafting of the manuscript; critical revision of the manuscript for important intellectual content.
Funding The study was sponsored by Corrona. Corrona has been supported through contracted subscriptions in the last two years by AbbVie, Amgen, Boehringer Ingelheim, Bristol-Myers Squibb, Crescendo, Eli Lilly, Genentech, Gilead, GSK, Horizon Pharma USA, Janssen, Merck, Momenta Pharmaceuticals, Novartis, Pfizer, Roche, UCB and Valeant.
Competing interests PJM: research grants: AbbVie, Amgen, BMS, Celgene, Janssen, Lilly, Novartis, Pfizer, Sun, UCB; consulting: AbbVie, Amgen, BMS, Celgene, Janssen, Lilly, Novartis, Pfizer, Sun, UCB; speakers’ bureau: AbbVie, Amgen, BMS, Celgene, Genentech, Janssen, Novartis, Pfizer, UCB. CJE: employee at Corrona and advisory board for Merck. WJH, TMM, JRL, MJM and WNM: employees and stockholders at Eli Lilly. AWA has served as investigator, advisor and/or consultant to AbbVie, Janssen, Novartis, Lilly, Regeneron, Sanofi, Leo, Science 37, Modernizing Medicine and Ortho Dermatologics. SR and RD: employees at Corrona. JDG: employee and shareholder at Corrona; consultant for Genentech, Janssen, Novartis, Pfizer and Eli Lilly.
Patient consent for publication Not required.
Ethics approval Sponsor approval was obtained through a central Institutional Review Board (IRB). For academic investigative sites that did not receive a waiver to use the central IRB, full board approval was obtained from the respective governing IRBs and documentation of approval was submitted to Corrona before initiating any study procedures.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data may be obtained from a third party and are not publicly available.