Cross-sectional quantitative validation of the paediatric Localized Scleroderma Quality of Life Instrument (LoSQI): A disease-specific patient-reported outcome measure.

BACKGROUND: The Localized Scleroderma Quality of Life Instrument (LoSQI) is a disease-specific patient-reported outcome (PRO) measure designed for children and adolescents with localized scleroderma (LS; morphea). This tool was developed using rigorous PRO methods and previously cognitively tested in a sample of paediatric patients with LS. OBJECTIVE: The purpose of this study was to evaluate the psychometric properties of the LoSQI in a clinical setting. METHODS: Cross-sectional data from four specialized clinics in the US and Canada were included in the analysis. Evaluation included reliability of scores, internal structure of the survey, evidence of convergent and divergent validity, and test-retest reliability. RESULTS: One hundred and ten patients with LS (age: 8-20 years) completed the LoSQI. Both exploratory and confirmatory factor analysis supported the use of two sub-scores: Pain and Physical Functioning, and Body Image and Social Support. Correlations with other PRO measures were consistent with pre-specified hypotheses. LIMITATIONS: This study did not evaluate longitudinal validity or responsiveness of scores. CONCLUSION: Results from a representative sample of children and adolescents with LS continue to support the validity of the LoSQI when used in a clinical setting. Future work to evaluate the responsiveness is ongoing.

A novel patient-reported outcome for paediatric localized scleroderma: a qualitative assessment of content validity.

BACKGROUND: According to current standards, no existing patient-reported outcome (PRO) measures have high-quality validity evidence for use with individuals diagnosed with paediatric localized scleroderma (LS). This severely hinders patient-centred LS-focused research, including much needed clinical trials. OBJECTIVES: To develop a valid health-related quality of life measure for individuals with paediatric LS and to qualitatively evaluate its content validity using a patient-centred approach. METHODS: Previously collected qualitative data from youth with LS and their caregivers was used to develop items. The resulting item set was administered in a clinical setting to participants aged 8-18 years old. Cognitive interviews were used to evaluate time to survey completion, readability/understanding of the items, appropriateness of the recall period and construct representation. RESULTS: Seventeen children and adolescents with LS participated in the study. Interviews supported readability, understanding of the items and appropriateness of the recall period in individuals > 10 years old. Revisions were made to simplify the instructions and to be more inclusive of different subtypes of LS. Three items were added to improve content representation. CONCLUSIONS: Content validity was supported by the patient-centred development process of the outcome measure and via direct feedback from individuals with LS and their families. Although an important first step, the resulting PRO, termed the Localized Scleroderma Quality of Life Instrument, should be further evaluated in a larger sample before being implemented. What's already known about this topic? No current health-related quality of life (HRQoL) measures have been created using direct input from children and adolescents with localized scleroderma (LS). When compared with qualitative reports of HRQoL impact in youth with all LS subtypes, no existing patient-reported outcome (PRO) measures have appropriate content validity for individuals with paediatric LS. What does this study add? This study proposes a novel LS-specific PRO and is the first qualitative assessment of content validity for any PRO measure in this population. Results from cognitive interviews with children and adolescents support the content validity of the newly developed item set and its ability to capture HRQoL impact in a clinical context. What are the clinical implications of this work? Incorporating a content-valid PRO of HRQoL impact into clinical practice would allow for the valid, ongoing capture of patient experience in LS. Although content validity is an important and necessary step in the process of evaluating validity, items within this novel measure will undergo additional psychometric evaluation before implementation in research and clinical settings.