Updated Psoriatic Arthritis Outcome Measures Offer Greater Inclusion of Patient Concerns
Ten domains were identified for inclusion in the PsA core domain set for clinical trials.
Outcome measurement tools for psoriatic arthritis (PsA) have been updated by the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) and endorsed by Outcome Measures in Rheumatology (OMERACT) to better assess life impact on patients.1 The update involved a meticulous process of data collection, survey, and consensus proceedings.
An earlier set of PsA core set of domains for use in randomized controlled trials (RCTs) and longitudinal observational studies had been developed by GRAPPA and endorsed by OMERACT in 2006.2 In acknowledging that the science of outcomes research and our knowledge about PsA have evolved during the last decade, the GRAPPA-OMERACT PsA working group set about developing a new international consensus that involved both patients and physicians.
The work began with a systematic literature review of domains assessed in PsA-focused RCTs, longitudinal observational studies, and registries. International patient and physician focus groups that discussed issues relevant to patients with PsA ensued. Domains derived from the literature search and focus groups were combined, resulting in 39 unique domains.
Two phases of a survey followed in which patients and physicians separately rated the domains. Finally, an international face-to-face consensus meeting of patients and physicians took place at which nominal group technique was used to agree on a preliminary core set of the 7 to 10 domains considered to be most important for both patients and physicians for measurement in PsA RCTs and longitudinal observational studies. The domains were then discussed and voted on at the 2016 OMERACT Conference in Whistler, British Columbia, Canada.
A total of 100 patients, who were selected to represent all phenotypes of PsA, and 124 physicians, selected from among GRAPPA members, were invited to participate in the survey. In total, 50 patients (50.0%) and 75 physicians (60.5%) completed the survey. The face-to-face consensus meeting included 12 patients, 12 physicians, and 2 nonvoting GRAPPA fellows. Participants rated the importance of each domain using an 11-point numerical rating, discussed the domains in a breakout session, and ultimately voted for individual domains and the final core domain set.
They arrived at 10 domains for inclusion in the PsA core domain set for clinical trials: musculoskeletal disease activity, skin disease activity, pain, patient global, physical function, participation, emotional well-being, fatigue, systemic inflammation, and structural damage. Economic cost also was recommended for inclusion but was deemed not essential for measurement in all clinical trials.
A consensus was then officially formulated by 130 OMERACT participants at the 2016 meeting. A 90% vote resulted in a recommendation that the 8 following outcomes be included in all RCTs and longitudinal observational studies: musculoskeletal disease activity, skin disease activity, pain, patient global, physical function, health-related quality of life, fatigue, and systemic inflammation. Strongly recommended but not required were economic cost, emotional well-being, participation, and structural damage. Outcomes needing further study were independence, sleep, stiffness, and treatment burden.
Changes between the 2006 and 2016 PsA outcomes measures are the moving of fatigue to the inner core and inclusion of participation and emotional well-being as strongly recommended but not mandatory domains. Enthesitis and dactylitis have also been moved to the inner core and combined with peripheral arthritis under the category of musculoskeletal disease activity.
The study authors commented that the updated outcomes measurement model may facilitate shared decision-making between patients and physicians and improve therapy selection and overall patient care.
Summary and Clinical Applicability
After 10 years, the domains for outcome measurement in clinical trials of psoriatic arthritis were updated by the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis and endorsed by Outcome Measures in Rheumatology. The updated domains allow for improved assessment of life impact on patients. The updated outcomes measurement model may facilitate shared decision-making between patients and physicians and improve therapy.
The main limitation of the process was that the survey and consensus meeting, meant for international participation, were only given in English and French, which limited selection of patients to those speaking one of these languages
- Orbai AM, de Wit M, Mease P, et al. International patient and physician consensus on a psoriatic arthritis core outcome set for clinical trials [published online September 9, 2016]. Ann Rheum Dis. doi: 10.1136/annrheumdis-2016-210242
- Gladman DD, Mease PJ, Strand V, et al. Consensus on a core set of domains for psoriatic arthritis. J Rheumatol. 2007;34:1167-1170.