Article Figures & Data
Figures
- Figure 1.
The OMERACT Filter 2.1 Instrument selection algorithm is represented at the left (OMERACT handbook). The COMPACT workflow through OMERACT Filter 2.1 is represented at the right. The 4 signaling questions must be addressed in OMERACT Filter 2.1 instrument selection (items 1–4) in the left part of the figure. Following the OMERACT process, participants provide input initially into domain match and feasibility, and subsequently into the approach and results of evaluation of additional measurement properties, as well as the final voting for inclusion as core outcome measure(s). For each domain and candidate outcome measure, the OFISA Filter 2.1 is applied until a core outcome measure has been selected. The process is repeated for each core domain. Once each core domain has at least 1 corresponding core outcome measurement instrument, the PsA Core Outcome Measurement Set is complete. OMERACT: Outcome Measures in Rheumatology; COMPACT: Core Outcome Measures in Psoriatic Arthritis; OFISA: OMERACT Filter Instrument Selection Algorithm; GRAPPA: Group for Research and Assessment of Psoriasis and Psoriatic Arthritis; PsA: psoriatic arthritis; COSMIN: consensus-based standards for the assessment of health measurement instruments; LOS: longitudinal observational study; RCT: randomized controlled trial.
- Figure 2.
OMERACT summary of evidence for measurement properties of PsAID12. Color designates quality of evidence: green = good methods used, use this evidence; amber = some cautions but we will use this evidence. In the rating row, color designates overall evidence-based instrument rating for the core instrument set: green = at least 2 pieces of evidence with good methods and consistent findings of adequate or better performance; amber = a noncritical limitation in the evidence was found. The plus signs mean adequate or better performance of the instrument according to that study (for each measurement property studied). OMERACT: Outcome Measures in Rheumatology; PsAID: Psoriatic Arthritis Impact of Disease; TAG: Technical Advisory Group; SOMP: Summary of Measurement Properties.
Tables
Discussion Points by Topic Overall Process and Evidence It was noted that a significant amount of work had gone into appraising the instruments, and that both were backed by a substantial body of evidence.
A number of participants felt that the instrument could achieve an overall green rating given the body of evidence supporting Domain Match, Feasibility, and Construct validity, whereas other participants felt that discrimination was a critical aspect of an instrument and that an “Amber” rating in any of the discrimination subcategories should result in an overall amber rating.
Content Validity It was noted that the PsAID questionnaire identifies items that may not be relevant to all patients, and concerns around how this might affect the overall score. There were also some concerns regarding the anchors used.
Whether patients could conceptualize “due to PsA” is referring to their condition if they do not have arthritis manifestations. Probably not a major concern, because patients voted positively for domain match. Whether patients’ ratings for items like embarrassment/fatigue/others can really differentiate that it is effect of PsA rather than other comorbidities (disease attribution).
Feasibility Weighted scores affect feasibility.
Construct Validity Potentially different constructs simultaneously assessed by items work/leisure (#4), anxiety/fear/uncertainty (#9), embarrassment/shame (#10).
Concern these items may not be as sensitive to change with treatment.
Discrimination Some confusion regarding the use of a LOS to assess discrimination, with many people in the breakout group believing that this evidence must come from an RCT. Some participants felt that discrimination in clinical trials was a critical aspect for an instrument, particularly as the objective is to find instruments to be used in RCT, and this was noted to be especially important to Industry. One of 8 breakout groups suggested RCT discrimination should have been white rather than amber (15/17).
OMERACT TAG has clarified that cohort study longitudinal data can be taken as bronze-level evidence. Since RCT information is missing, can proceed with amber based on LOS and mandatory to address the gaps of knowledge: RCT data. Research agenda: RCT discrimination and thresholds of meaning.
Suggestions Skin item (#3): change attribution to psoriasis instead of PsA.
Inconsistency across anchors for the 12 items when some would prefer consistent anchors.
Other Based on PsAID12, we cannot calculate utilities or economic analysis. There may be interpretability of some questions.
Overlap with other domains such as physical function and fatigue was noted.
Agreement with PsAID12 amber (or better) endorsement as core instrument for PsA RCT and LOS across breakout groups (all considered together): 71/81(88%). OMERACT: Outcome Measures in Rheumatology; PsAID: Psoriatic Arthritis Impact of Disease; PsA: psoriatic arthritis; LOS: longitudinal observational study; RCT: randomized controlled trial; TAG: Technical Advisory Group.
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