Construct validity and responsiveness of feasible composite disease activity measures for use in daily clinical practice in patients with psoriatic arthritis

OBJECTIVE: There is a need for a widely accepted comprehensive disease activity measure for use in daily practice in patients with psoriatic arthritis (PsA). For this reason, the 3-item Visual Analogue Scale (3VAS) and 4-item Visual Analogue Scale (4VAS) were developed. This study aimed to test construct validity and responsiveness of the 3VAS and 4VAS in a population of patients with newly diagnosed PsA receiving usual care. METHODS: Components of the 3VAS (physician global, patient global, patient skin) and 4VAS (physician global, patient pain, patient joint, patient skin) were scored on 0-10 VAS scales. Agreement of low disease activity (LDA) state between 3VAS/4VAS and other composite measures was tested using Venn diagrams. Construct validity and responsiveness (3-month interval) were assessed using Spearman correlation coefficients and standardised response means (SRM) with effect sizes (ES), respectively, following hypothesis generation. Both 3VAS/4VAS were also compared with several patient-reported outcome measures. RESULTS: Data from 629 patients were used. Both 3VAS (ES=0.48, SRM 0.52) and 4VAS (ES=0.48, SRM=0.50) showed responsiveness similar to Disease Activity in PSoriatic Arthritis (DAPSA) and Disease Activity Score-28 (DAS28). Both measures had a strong correlation with DAPSA (r=0.80-0.87), Psoriatic Arthritis Disease Activity Score (PASDAS) (r=0.89) and Routine Assessment of Patient Index Data 3 (RAPID3) (r=0.84-0.92). 3VAS and 4VAS had the highest agreement with PASDAS in categorising patients to LDA at 12 months. CONCLUSION: This is the first study assessing the performance of the 3VAS and 4VAS in an observational cohort of patients with early PsA. Both measures have promising performance characteristics, showing strong correlations and good discrimination with existing composite measures. The 4VAS may be the preferred version with better face validity.</p

The burden of psoriasis in patients with early psoriatic arthritis

Objectives: Psoriasis impacts health-related quality of life (HRQoL) in PsA patients. However, this is not adequately measured with a general HRQoL questionnaire. The aim of this study was to quantify the degree of psoriasis evolution in PsA patients over the first year of follow-up and to evaluate whether the impact of psoriasis on HRQoL can be adequately measured with a dermatology-specific HRQoL questionnaire. Methods: Data were used from PsA patients in the Dutch south west Early Psoriatic Arthritis cohort. Psoriasis severity was measured with the Psoriasis Area and Severity Index (PASI). Dermatology-specific HRQoL was assessed with the Skindex-17 questionnaire. We used a Sankey diagram to illustrate the evolution of psoriasis severity during the first year of follow-up. To assess the association between psoriasis severity and the symptoms and psychosocial subscale of the Skindex-17, a linear regression analysis with hierarchical variable selection and zero-inflated negative binominal regression analysis were performed, respectively. Results: We included 644 patients; 109 (17%) patients had no psoriasis (PASI = 0), 456 (71%) had mild psoriasis (PASI 12). Psoriasis severity did not fluctuate much during the first year. PASI was significantly associated with both subscales of the Skindex-17 at baseline and 12 months. Conclusion: Psoriasis severity in PsA patients is mostly mild but impacts HRQoL when measured using a dermatology-specific HRQoL questionnaire. For optimal management of PsA patients, we recommend rheumatologists acquire information on skin burden by using a dermatology-specific HRQoL questionnaire

A Practical Guide for Assessment of Skin Burden in Patients With Psoriatic Arthritis

OBJECTIVE: Rheumatologists play a pivotal role in the management of patients with psoriatic arthritis (PsA). Due to time constraints during clinic visits, the skin may not receive the attention needed for optimal patient outcome. Therefore, the aim of this study was to select a set of core questions that can help rheumatologists in daily rheumatology clinical practice to identify patients with PsA with a high skin burden. METHODS: Baseline data from patients included in the Dutch South West Psoriatic Arthritis (DEPAR) cohort were used. Questions were derived from the Skindex-17 and Dermatology Life Quality Index (DLQI) questionnaires. Underlying clusters of questions were identified with an exploratory principal component analysis (PCA) with varimax rotation, after which a 2-parameter logistic model was fitted per cluster. Questions were selected based on their discrimination and difficulty. Subsequently, 2 flowcharts were made with categories of skin burden severity. Clinical considerations were specified per category. RESULTS: In total, 413 patients were included. The PCA showed 2 underlying clusters: a psychosocial domain and a domain assessing physical symptoms. We selected these 2 domains. The psychosocial domain contains 3 questions and specifies 4 categories of skin burden severity. The physical symptoms domain contains 2 questions and categorizes patients in 1 out of 3 categories. CONCLUSION: We have selected a set with a maximum of 5 questions that rheumatologists can easily implement in their consultation to assess skin burden in patients with PsA. This practical guide makes the assessment of skin burden more accessible to rheumatologists and can aid in clinical decision making