Oliver FitzGerald

Psoriatic arthritis (PsA) is a complex, multisystem disease with no diagnostic criteria and discordant approaches to assessing disease activity and response to treatment. PsA is part of the Psoriatic Disease spectrum, encompassing cutaneous psoriasis and nail changes, PsA and in some cases, uveitis and inflammatory bowel disease. The HIPPOCRATES consortium is addressing unmet needs in PsA and has now established a harmonised data platform, the Secure HIPPOCRATES Data Management Platform (SHDMP), which will be transformative in providing researchers with the ability to interrogate at scale psoriatic disease datasets. The SHDMP datasets are diverse and include people with psoriasis being followed for the development of PsA, as well as cross-sectional, observational and randomised control trial data on people with PsA. To better understand and describe the nature of the SHDMP datasets, the HIPPOCRATES consortium has now defined and agreed on the terms that will be applied to each dataset. In this short report, the process adopted to obtain consensus on the dataset definition and the final set of terms agreed upon is described and discussed. The agreement on the terms to be used will greatly enhance a researcher’s ability to select the appropriate SHDMP datasets to study.

Background: Up to one-third of people living with psoriasis develop psoriatic arthritis (PsA), and the majority have active psoriasis prior to the development of arthritis. Clinical risk factors, such as nail involvement, in conjunction with novel blood biomarkers, could improve PsA risk monitoring and early diagnosis. Objectives: The aim of the HIPPOCRATES Prospective Observational Study (HPOS— www.hpos.study ) is to follow a cohort living with psoriasis and identify risk factors for the development of PsA. Design: HPOS is a patient-driven online prospective European observational cohort. Methods: Adult participants with psoriasis but with no prior diagnosis of PsA are eligible. Participants are invited to provide consent and join the study online. They complete a semi-structured questionnaire to collect data on demographics, psoriasis, comorbidities, risk factors for PsA, and the Psoriasis Epidemiology Screening Tool screening questionnaire. Follow-up is conducted through a questionnaire every 6 months. The primary outcome is the new onset of PsA confirmed by a diagnosis from their doctor. The study will also collect peripheral blood samples from a subset of participants for biomarker identification. Ethics: This study follows the principles of the Declaration of Helsinki. To date, ethical approval has been granted by independent ethical committees in 10 countries. Discussion: Studying a cohort of individuals with psoriasis will allow us to identify risk factors for arthritis development and to develop a risk calculator. This can support focused efforts on screening, patient education, and even studies looking to delay or prevent the onset of arthritis. This study, run via remote online data collection, provides an efficient way to recruit a large cohort (25,000) across multiple countries. However, challenges have had to be addressed with some key changes in study design, ethical review, and recruitment strategies required for each individual country. Trial registration: HPOS, Clinicaltrials.gov ID: NCT05858528, IRAS number 325080; https://clinicaltrials.gov/study/NCT05858528?locStr=United%20Kingdom&country=United%20Kingdom&cond=Psoriasis&term=HPOS&aggFilters=status%3Anot%20rec&rank=1 .

Significant progress toward several key initiatives was presented during the Project Key Advances session of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) 2024 annual meeting. Highlights included advancements from the Collaborative Research Network (CRN), with contributions from the Health Initiatives in Psoriasis and Psoriatic Arthritis Consortium European States (HIPPOCRATES) and developments in the complex-to-manage (C2M)/difficult-to-treat (D2T) psoriatic arthritis project. The presentation also included an update on the GRAPPA educational slide library. These activities underscore GRAPPA’s continued dedication to fostering collaboration that advances psoriatic disease education and research toward improved patient outcomes.

Psoriasis is a common, debilitating immune-mediated skin disease. Genetic studies have identified biological mechanisms of psoriasis risk, including those targeted by effective therapies. However, the genetic liability to psoriasis is not fully explained by variation at robustly identified risk loci. To refine the genetic map of psoriasis susceptibility we meta-analysed 18 GWAS comprising 36,466 cases and 458,078 controls and identified 109 distinct psoriasis susceptibility loci, including 46 that have not been previously reported. These include susceptibility variants at loci in which the therapeutic targets IL17RA and AHR are encoded, and deleterious coding variants supporting potential new drug targets (including in STAP2, CPVL and POU2F3). We conducted a transcriptome-wide association study to identify regulatory effects of psoriasis susceptibility variants and cross-referenced these against single cell expression profiles in psoriasis-affected skin, highlighting roles for the transcriptional regulation of haematopoietic cell development and epigenetic modulation of interferon signalling in psoriasis pathobiology.

It is known that 25%–30% of individuals with cutaneous psoriasis (PsC) will develop psoriatic arthritis (PsA). To date, the reasons for the development of PsA in individuals with PsC have not been identified. Furthermore, there are considerable delays in the diagnosis and treatment of PsA, which lead to joint and bone deformation and chronic pain. It is therefore important to develop more precise diagnostic and screening tools. In this narrative review of the literature, clinical risk factors and novel molecular biomarkers (genetic markers, blood and inflammatory markers, lipid, metabolite and protein biomarkers) have been evaluated. The review included 38 publications that were reported between May 2020 and May 2024. Similar to previous reviews, nail involvement was one of the strongest clinical risk factors for the development of PsA, while molecular biomarkers did not provide a clear and robust differentiation between PsC and PsA groups. The seemingly poor performance of molecular markers may be largely attributed to small study populations and heterogeneity in study designs. Data and sample sharing in large consortia such as HIPPOCRATES (Health initiatives in Psoriasis and PsOriatic arthritis ConsoRTium European States) could help to overcome the limitations of small studies and enable the development of more robust diagnostic and screening tools for PsA.

The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) 2023 annual meeting was held on July 13 to 15, 2023, in Dublin, Ireland, and was attended by 285 rheumatologists, dermatologists, trainees, patient research partners (PRPs), representatives of patient organizations, and industry partners. The 20th anniversary of GRAPPA was celebrated with a special presentation and archival video. Ahead of the meeting, the PRP Network met, a workshop was held by the International Dermatology Outcome Measures (IDEOM) group, and there was a workshop in which researchers discussed advancing ultrasound use to improve the management of psoriatic disease (PsD). Young-GRAPPA also held a workshop and business meeting. Multiple presentations highlighted important topics currently influencing PsD, including ensuring that patients are included in advancing research, the role of depression in PsD, the use of magnetic resonance imaging for spinal lesions, and animal models of PsD, among others. Debates focused on whether biologics should be used for mild psoriasis, whether methotrexate should remain the first-line treatment for PsD, and whether PsD is really a primary enthesitis driving joint synovitis. Here we provide an overview of the features of the GRAPPA 2023 annual meeting and introduce the manuscripts published together in this supplement as a meeting report.

At the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) 2023 annual meeting, members were updated on a number of ongoing activities during the key project update session. These activities included the Axial Involvement in Psoriatic Arthritis (AXIS) cohort, the Axial Psoriatic Arthritis Molecular and Clinical Characterization study, the Diagnostic Ultrasound Enthesitis Tool (DUET) study, the Sex- and Gender-Based Analysis of the Effectiveness of Advanced Therapies in Psoriatic Arthritis (SAGE-PsA) study, the Health Initiatives in Psoriasis and Psoriatic Arthritis Consortium European States (HIPPOCRATES), the GRAPPA slide library, and the GRAPPA treatment recommendations.