Photo Credit: Ivan Balvan
Bruce Strober, MD, PhD, published a paper recently in JAMA Dermatol focusing on disease burden measurements of meaning to patients with psoriasis.
At Maui Derm Hawaii, held January 22-26, 2024 in Maui, Bruce Strober, MD, PhD, presented as part of “Psoriasis Update: 2024.” Dr. Strober published a paper* recently in this area of study in JAMA Dermatol, focusing on disease burden measurements of meaning to patients with psoriasis.
*This study was not presented at the meeting.
The study delves into the establishment of meaningful within-patient change thresholds (MWPCTs) for the Psoriasis Symptoms and Signs Diary (PSSD) through the utilization of patient-reported anchors. The PSSD serves as a validated patient-reported outcome instrument, assessing the severity of psoriasis signs and symptoms from the patient’s perspective. While a change of −40 points from baseline has been suggested as a clinically meaningful improvement, recent regulatory guidelines advocate for deriving thresholds using patient-reported anchors rather than clinician-rated methods. “Change from baseline score on the validated Psoriasis Symptoms and Signs Diary (PSSD) is a widely used, patient-reported end point in clinical trials for psoriasis,” wrote Dr. Strobe and colleagues. “Meaningful score change thresholds anchored to patient-reported assessments have not been established in a clinical trial setting.”
The study leveraged data from the POETYK PSO-1 phase 3 clinical trial conducted in patients with plaque psoriasis. The POETYK PSO-1 trial was conducted from August 7, 2018 to September 2, 2020 and encompassed 666 patients who completed the PSSD daily, providing ratings for five skin symptoms and six skin signs associated with psoriasis on an 11-point scale. Patients were categorized into different treatment groups (deucravacitinib, placebo, and apremilast). The Patient Global Impression of Change (PGI-C) and Patient Global Impression of Severity (PGI-S) served as patient-reported anchors to evaluate the overall impact of psoriasis on patients’ lives and the severity of psoriasis symptoms, respectively.
The analysis included 609 patients who completed at least one PSSD item at baseline and a postbaseline visit. Correlation coefficients between changes in PSSD scores and anchors indicated suitability for MWPCT derivation. The study identified significant within-group improvements in PSSD scores at week 16 for the “a little better” PGI-C category and the 1-point improvement PGI-S category. Cumulative distribution function curves demonstrated clear separation between no-change and improvement groups, supporting the discriminative ability of the anchors.
Anchored analysis suggested an MWPCT of 15 points for domain and total scores on the PSSD. Higher MWPCTs of 25 and 30 points were identified for improvements on both PGI-C and PGI-S anchors. These estimates exceeded distribution-based estimates, underscoring the importance of patient-reported anchors in determining meaningful changes. “Score improvement of at least 15 points from baseline reflected meaningful within-patient change anchored to the PGI-C,” wrote Dr. Strober and team in JAMA Dermatol. “Score improvements of 25 points were supported by both the PGI-C and the PGI-S, while a 30-point score change identified patients with greater improvements in their psoriasis symptoms and signs.” The study delved into individual PSSD items, supporting the meaningfulness of a 2-point improvement.
While the study provides valuable insights into the interpretability of PSSD scores in the context of psoriasis clinical trials, it acknowledges certain limitations. The lowest MWPCT identified, −15 points, corresponds to a rating of change rather than the rating of concept, introducing a potential bias. Additionally, the study did not examine the applicability of MWPCTs to worsening psoriasis symptoms or signs.
That said, the analysis contributes significantly to enhancing the interpretability of PSSD scores in patients with psoriasis by determining meaningful within-patient change thresholds. The reliance on patient-reported anchors, specifically the PGI-C and PGI-S, represents a significant advance in aligning with regulatory guidelines and ensuring patient-centric interpretations of changes in PSSD scores. The identified MWPCTs allow for meaningful responder analyses, providing valuable insights into the efficacy of interventions in the management of patients with psoriasis. The study’s findings pave the way for a more nuanced understanding of patient-reported outcomes and their relevance in assessing the impact of psoriasis interventions on individuals’ lives. “This analysis suggests that PSSD score improvements of 15, 25, or 30 points represent increasing improvements in disease burden that are meaningful to patients with psoriasis,” concluded Dr. Strober and colleagues in JAMA Dermatol.
For more information regarding Maui Derm 2024, visit the conference website. Check here often for conference updates, psoriasis-focused abstracts and features, and more!
