In a clinical trial, published in Advances in Therapy, researchers evaluated the Psoriasis Symptoms and Impacts Measure (P-SIM) patient-reported outcome (PRO) tool and found it was effective in collecting accurate experiences of patients with psoriasis. “The three items of the P-SIM assessed here demonstrated robust psychometric properties, including test–retest reliability, convergent and known-group validity and sensitivity to change in the concepts that they intended to measure,” summarized the study’s lead author, Alice Gottlieb, MD, PhD.
Throughout the BE RADIANT phase IIIB trial, the P-SIM electronically assessed the itching, skin pain, and scaling symptoms of patients with plaque psoriasis on a scale of zero (no symptoms) to 10 (very severe).
Test-retest reliability was determined using intraclass correlations. Convergent validity between P-SIM and other PRO and clinician-reported outcome (ClinRO) scores were assessed. Known-groups validity was determined by comparing mean P-SIM scores between subgroups based on the Psoriasis Area and Severity Index (PASI), and Investigator’s Global Assessment (IGA) scores. Responsiveness was evaluated through correlation in changes from baseline P-SIM scores and other relevant scores.
The three P-SIM scores yielded high intraclass coefficients (> 0.70). By Week 48, the three P-SIM items had moderate (> 0.30 and ≤ 0.50) to strong (> 0.50) correlations with other PROs, and weaker correlations with ClinROs. Significant differences in between-subgroup scores were observed in all three P-SIM items for almost all known-group comparisons. Changes from baseline in the P-SIM and other relevant scores were above the acceptable threshold of ≤ 0.30.
Limitations of this study included a lack of racial diversity, which restricts the generalizability of the results. Authors also listed low completion rate at week 48 as a potential limitation, though they noted that, results at Week 32 were generally consistent with those at Week 48.
According to the authors, the analysis supported the “validity, reliability and sensitivity to change of the P-SIM in assessing key symptoms (itching, skin pain and scaling) in patients with moderate to severe plaque psoriasis,” as administered by a hand-held device during patient visits. Researchers also concluded that a greater than four-point reduction from baseline indicated marked improvement for patients with psoriasis, and suggested it as a marker for meaningful change during treatment.
Source: Advances in Therapy