Composite Measures Provide More Accurate Picture of PsA Activity

While investigators are eyeing biomarkers as a future tool for gauging treatment response in patients with psoriatic arthritis, currently available tools for measuring outcomes focus on either assessing individual disease domains or combining multiple domains into a composite measurement.

“There are 6 principal domains that have previously been identified by GRAPPA [Group for Research and Assessment of Psoriasis and Psoriatic Arthritis] in 2015 to help guide treatment and management of patients: arthritis, axial disease, enthesitis, dactylitis, and psoriatic skin and nail disease,” explained authors of a literature review published online in Musculoskeletal Care.

Recent evidence suggests, according to the article, that composite measurements provide a more accurate picture of disease activity and outcomes than individual disease domain measure.

The authors reviewed several composite measures, including minimal disease activity (MDA) criteria. Developed in 2010, MDA criteria include measures of tender and swollen joints, enthesitis, and pain, and have been shown to correlate highly with a symptom level acceptable to patients. Released in 2011, the Composite Psoriatic Disease Activity Index (CPDAI) assesses each psoriatic arthritis domain in the context of disease activity, as well as its effect on function and quality of life. Although easy to use and well validated, the CPDAI requires more time and questionnaires than other composite scales, the authors explained.

Published several years after the CPDAI, the Psoriatic Arthritis Disease Activity Score (PASDAS) spans eight domain measures and includes clinician-reported information, such as domain-specific symptoms and C-reactive protein levels, and patient input. Both CPDAI and PASDAS have shown good responsiveness to change and the ability to differentiate between treatment and placebo, according to the review. Meanwhile, the newer Psoriatic Arthritis 5-Thermometer scales incorporates pain, fatigue, physical function, skin disorders, and depression.

For a more patient-centric perspective, validated patient-reported outcome measurements options include the Psoriatic Arthritis Quality of Life and the Psoriatic Arthritis Impact of Disease questionnaires. Meanwhile, the identification of biomarkers that eventually could be used to assess clinically meaningful outcomes has generated growing interest.

“Although still in its infancy, the early findings from … small studies suggest that a combinatorial approach of biomarkers may prove feasible in the near future for assessing disease activity and potentially response to therapies,” the authors reported.

—Jolynn Tumolo

Reference:
Hackett S, Coates LC. Outcome measures in psoriatic arthritis: where next? Musculoskeletal Care. 2022;20 Suppl 1(Suppl 1):S22-S31. doi:10.1002/msc.1692