Symptom Experience and Content Validity of the Psoriasis Symptom Scale (PSS) in Patients with Generalized Pustular Psoriasis (GPP)

Psychometric validation of the Psoriasis Symptom Scale, Functional Assessment of Chronic Illness Therapy-Fatigue and pain-Visual Analogue Scale in patients with generalized pustular psoriasis

BACKGROUND

Generalized pustular psoriasis (GPP) is a rare, chronic, inflammatory skin disease associated with considerable patient burden. The Psoriasis Symptom Scale (PSS), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) and pain-Visual Analogue Scale (pain-VAS) are patient-reported outcomes (PROs) that have not yet been validated in patients with GPP.

OBJECTIVES

To evaluate the psychometric properties of the PSS, FACIT-Fatigue and pain-VAS using data from Effisayil 1, a randomised trial of spesolimab in patients with moderate-to-severe GPP.

METHODS

Inter-item correlations and confirmatory factor analysis (CFA) were performed using Week 1 data. Internal consistency was assessed with Cronbach's α coefficient using baseline and Week 1 data. Test-retest reliability was assessed using intraclass correlation coefficients (ICCs); change data for the GPP Physician Global Assessment total score and pustulation subscore were used to define a stable population. Convergent validity was assessed at baseline and Week 1 using Spearman's rank-order correlations. Known-groups validity was measured by analysis of variance using Week 1 data. Ability to detect change from baseline to Week 1 was evaluated by analysis of covariance.

RESULTS

Inter-item and item-to-total correlations were moderate or strong for most PSS and FACIT-Fatigue items. CFA demonstrated the unidimensionality of the PSS and FACIT-Fatigue, with high factor loadings for most items (PSS range, 0.75-0.94; FACIT-Fatigue range, 0.11-0.93) and acceptable fit statistics. Both scores demonstrated internal consistency (Cronbach's α, 0.71 and 0.95, respectively). The PSS, FACIT-Fatigue and pain-VAS demonstrated test-retest reliability (ICCs ≥0.70) and good evidence of convergent validity. Furthermore, the PROs could differentiate between known groups of varying symptom severity (range, p < 0.0001-0.0225) and detect changes in symptom severity from baseline to Week 1 (range, p < 0.0001-0.0002).

CONCLUSIONS

Overall, these results support the reliability, validity and ability to detect change of the PSS, FACIT-Fatigue and pain-VAS as PROs in patients with GPP.

Health-related quality of life in patients with generalized pustular psoriasis: A systematic literature review

Generalized pustular psoriasis (GPP) is a rare, chronic, neutrophilic inflammatory skin disease characterized by episodes of widespread eruption of sterile, macroscopic pustules that can be accompanied by systemic inflammation and symptoms. A systematic literature review and narrative synthesis were conducted to determine the impact of GPP on patients' health-related quality of life (HRQoL) and patient-reported severity of symptoms and to compare its impact to patients with plaque psoriasis (plaque PsO). Searches were undertaken in Embase, MEDLINE and the Cochrane Library from 1 January 2002 to 15 September 2022. Screening was carried out by two reviewers independently. Outcome measures included generic (e.g. EQ-5D, SF-36) and dermatology-specific (e.g. DLQI) clinical outcome assessments, and other relevant patient-reported outcome measures (PROMs) (e.g. severity of pain measured by a numerical rating scale). Overall, 20 studies were found to be eligible for inclusion, of which seven also had data for plaque PsO. The DLQI was the most frequently reported outcome measure (16 out of 20 studies). When reported, mean DLQI (SD) scores varied from 5.7 (1.2) to 15.8 (9.6) across the studies, indicating a moderate to very large effect on HRQoL; the wide range of scores and large SDs were explained by the small population sizes (n ≤ 12 for all studies except two). Similar ranges and large SDs were also observed for other measures within individual studies. However, in general, people with GPP reported a greater impact of their skin condition on HRQoL, when compared to people with plaque PsO (i.e. higher DLQI scores) and higher severity for itch, pain and fatigue. This systematic review highlighted the need for studies with a larger population size, a better understanding of the impact of cutaneous and extracutaneous symptoms and comorbidities on HRQoL during and between GPP flares, and outcome measures specifically tailored to the unique symptoms and the natural course/history of GPP.

Brodalumab for the Treatment of Moderate-to-Severe Psoriasis: An Expert Delphi Consensus Statement

Brodalumab is a recombinant, fully human immunoglobulin IgG2 monoclonal antibody specifically targeted against interleukin-17RA that has been approved for the treatment of moderate-to-severe psoriasis in Europe. We developed a Delphi consensus document focused on brodalumab for the treatment of moderate-to-severe psoriasis. Based on published literature and their clinical experience a steering committee drafted 17 statements covering 7 domains specific to the treatment of moderate-to-severe psoriasis with brodalumab. A panel of 32 Italian dermatologists indicated their level of agreement using a 5-point Likert scale (from 1 = "strongly disagree" to 5 = "strongly agree") using an online modified Delphi method. After the first round of voting (32 participants), positive consensus was reached for 15/17 (88.2%) of the proposed statements. Following a face-to-face virtual meeting, the steering committee decided that 5 statements would form "main principles" and 10 statements formed the final list. After a second round of voting, consensus was reached in 4/5 (80%) of the main principles and 8/10 (80%) for consensus statements. The final list of 5 main principles and 10 consensus statements identify key indications specific to the use of brodalumab in the treatment of moderate-to-severe psoriasis in Italy. These statements aid dermatologists in the management of patients with moderate-to-severe psoriasis.