Development and validation of a patient-reported outcome in systemic sclerosis: the Hand scleroDerma lived Experience (HAnDE) scale

Background Hand involvement in systemic sclerosis (SSc) is at the core of the disease, with a substantial impact on both functional aspects and quality of life. There is no patient-reported outcome (PRO) scale globally assessing hand involvement in SSc. Objectives To develop and validate a PRO scale, the Hand scleroDerma lived Experience (HAnDE) scale, to assess the lived experience of hand involvement in patients with SSc. Methods This was an exploratory sequential mixed-methods study with two phases: (i) PRO development through an inductive process to analyse the structure of lived experience, involving 21 patients with SSc; and (ii) PRO validation by assessing the psychometric properties of the scale among 105 patients with SSc. Results Phase 1 enabled us to generate the 18-item provisional scale. From Phase 2, the mean (SD) total score of the scale was 29 center dot 16 (16 center dot 15). The item reduction process retained 16 items with five levels of answers (range 0-64). Internal consistency of the 16-item version was excellent (Cronbach's alpha = 0 center dot 946). Construct validity was very good, principal component analysis pointing towards a unidimensional instrument, with one factor explaining 56% of the variance, and concurrent validity being confirmed: Cochin Hand Function Scale r = 0 center dot 66; Health Assessment Questionnaire - Disability index r = 0 center dot 58; Hospital Anxiety and Depression Scale, anxiety r = 0 center dot 51, depression r = 0 center dot 4; Mouth Handicap in Systemic Sclerosis scale r = 0 center dot 61; 36-Item Short Form Health Survey, physical component r = -0 center dot 48, mental component r = -0 center dot 46; and Kapandji score r = -0 center dot 46. The correlations were statistically significant (P < 0 center dot 05). Conclusions We propose, for future trials and clinical practice in SSc, a new PRO, the HAnDE scale, that assesses all the dimensions - functional, aesthetic, relational, existential and emotional - of the lived experience of hand involvement in SSc.