Self-assessment of scleroderma skin:validation of the pastul questionnaire

Background/Aims The PASTUL (Patient self-Assessment of Skin Thickness in Upper Limb) questionnaire was developed during the COVID pandemic to allow self-assessment of skin remotely in systemic sclerosis (SSc). The aim of this study was to validate PASTUL, evaluate responsiveness and assess impact of skin on quality of life. Methods SSc patients were included in four centres. The PASTUL questionnaire specifies a grading of skin (normal, mild, moderate, severe thickness (0-3)) at eight sites corresponding to the modified Rodnan Skin Score (mRSS) with maximum score assigned to each site. Validity was assessed by comparing PASTUL scores with mRSS assessed by trained rheumatologists. Health Related Quality of Life (EQ5D5L and SSc HRQoL) and Scleroderma Skin Patient reported Outcome (SSPRO) were collected for construct validity, using Pearson's correlation coefficient (0-0.19 = negligible, 0.2-0.39 = weak, 0.4-0.59 = moderate, 0.6-0.79 = strong, 0.8-1.0 = very strong). Test-retest reliability was estimated using intraclass correlation coefficient (ICC). Patients were followed for six months. Results 149 patients were included, mean age 56.6 years (SD 13.2), 79.7% female, 78 (56.1%) had limited cutaneous SSc (lcSSc) and 61 (43.9%) diffuse cutaneous SSc (dcSSc). Mean disease duration was 12.8 years (SD 9.2), mean mRSS was 9.2 (SD 6.2). At baseline and six months follow-up, PASTUL and mRSS were strongly correlated (r=0.63 and r=0.78, p<0.001, respectively). Test-retest reliability, assessed in 75 patients, was very good (ICC of 0.83, 95% CI 0.74-0.89, p<0.001). Mean PASTUL scores were 9.3 (SD 6.2) at baseline and 8.5 (SD 6.6) at six months follow-up. In patients with >2 points increase in mRSS, change in PASTUL was significant (p=0.042). The standardized response mean (SRM) of mRSS and PASTUL in patients with clinically significant change in HRQoL (>0.082) was 0.29 and 0.24, respectively. Correlation between PASTUL and mRSS was moderate in lcSSc and strong in dcSSc (r=0.54 p<0.001, and 0.63 p<0.001, respectively). In patients with disease duration < 4 years, PASTUL was very strongly correlated with mRSS (r=0.84, p<0.001), and strongly correlated with HRQoL (EuroQoL, r= -0.67, p=0.004). SSPRO scores were not correlated with mRSS or PASTUL, but were moderatedly associated with SSc HRQoL scores (r=0.425, p<0.001). Conclusion Our preliminary results show that PASTUL is a valid and feasible outcome tool that adds a self-reported measure of skin severity to impact assessments like SSPRO. HRQoL was associated with skin thickening in patients with early disease. SRM was low and needs further assessment in a larger group. Disclosure J. Spierings: None. V.H. Ong: None. P.M.J. Welsing: None. M. Hughes: None. J.D. Pauling: None. F. Del Galdo: None. A.L. Herrick: None. C.P. Denton: None.