P151 Self-assessment of scleroderma skin thickness: development and evaluation of the PASTUL questionnaire

Spierings, Julia; Ong, Voon H; Denton, Christopher P

Background/Aims Evaluation of skin is central to both clinical practice and trials in systemic sclerosis (SSc). This is generally done with the modified Rodnan Skin Score (mRSS). Remote consultations are now widely implemented in response to the COVID-19 pandemic, which has inevitably limited evaluation of skin. To monitor skin during this pandemic and to further explore ways to assess skin, we developed the PASTUL (Patient self-Assessment of Skin Thickness in Upper Limb) questionnaire. The aim of this study was to evaluate feasibility and validity of the PASTUL in SSc. Methods The PASTUL questionnaire specifies a simple grading of skin as normal, mild, moderate, or severely thickened at eight sites of upper limb corresponding to mRSS. Assessed grades were converted to an integer scale [0, 1, 2, 3]. Detailed instructions for patients were provided. Scleroderma Skin PRO (SSPRO) and Scleroderma Health Assessment Disability Index (SHAQ-DI) were also completed. The mRSS was done in a selection of patients. Construct validity was evaluated by examining the correlation between PASTUL, mRSS, SSPRO and SHAQ-DI using Pearson’s correlation coefficient. Content validity was evaluated by scoring relevance, clarity and practical difficulty. Test-retest reliability was estimated using intraclass correlation coefficient (ICC). Results In total, 107 patients were invited of which 83 (77.6%) completed the questionnaires. The mRSS was undertaken in 61 patients. The PASTUL was completed by patients (83.1%) or by a partner/friend (16.9%). Mean PASTUL score was 11 (SD 6), mean HAQ-DI 1.47 (SD 0.76) and mean SSPRO 49.8 (SD 26.6). PASTUL and SSPRO physical limitations correlated strongly (0.62, p < 0.001). Correlations between PASTUL and total SSPRO and mRSS upper limbs were moderate to weak (0.59, 0.50 and 0.32 respectively). Correlation between PASTUL and mRSS was stronger in lcSSc compared to dcSSc patients (0.61 vs 0.29) and when assessed by a partner/friend compared to patients themselves (0.98 vs 0.45). The PASTUL demonstrated excellent test-retest reliability (ICC of 0.92) and good content validity. Conclusion Moderate and significant correlations of PASTUL scores with total SSPRO, physical limitation scores and mRSS support the usefulness of PASTUL as an outcome measure and indicates it’s potential for use in virtual clinical settings Disclosure J. Spierings: None. V.H. Ong: None. C.P. Denton: None.